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tcsh(1)                                                                tcsh(1)


       tcsh - C shell with file name completion and command line editing


       tcsh [-bcdefFimnqstvVxX] [-Dname[=value]] [arg ...]
       tcsh -l


       tcsh  is  an enhanced but completely compatible version of the Berkeley
       UNIX C shell, csh(1).  It is a command language interpreter usable both
       as an interactive login shell and a shell script command processor.  It
       includes a command-line editor  (see  The  command-line  editor),  pro-
       grammable  word  completion (see Completion and listing), spelling cor-
       rection (see Spelling correction), a  history  mechanism  (see  History
       substitution),  job  control  (see  Jobs) and a C-like syntax.  The NEW
       FEATURES section describes major  enhancements  of  tcsh  over  csh(1).
       Throughout  this  manual,  features  of  tcsh  not found in most csh(1)
       implementations (specifically, the 4.4BSD csh) are labeled with  `(+)',
       and features which are present in csh(1) but not usually documented are
       labeled with `(u)'.

   Argument list processing
       If the first argument (argument 0) to the shell is `-'  then  it  is  a
       login shell.  A login shell can be also specified by invoking the shell
       with the -l flag as the only argument.

       The rest of the flag arguments are interpreted as follows:

       -b  Forces a ``break'' from  option  processing,  causing  any  further
           shell arguments to be treated as non-option arguments.  The remain-
           ing arguments will not be interpreted as shell options.   This  may
           be used to pass options to a shell script without confusion or pos-
           sible subterfuge.  The shell will not  run  a  set-user  ID  script
           without this option.

       -c  Commands  are  read  from  the  following  argument  (which must be
           present, and must be a single  argument),  stored  in  the  command
           shell  variable  for  reference, and executed.  Any remaining argu-
           ments are placed in the argv shell variable.

       -d  The shell loads the directory stack from  ~/.cshdirs  as  described
           under Startup and shutdown, whether or not it is a login shell. (+)

           Sets the environment variable name to value. (Domain/OS only) (+)

       -e  The shell exits if any invoked  command  terminates  abnormally  or
           yields a non-zero exit status.

       -f  The  shell  does not load any resource or startup files, or perform
           any command hashing, and thus starts faster.

       -F  The shell uses fork(2) instead of vfork(2) to spawn processes. (+)

       -i  The shell is interactive and prompts for its top-level input,  even
           if it appears to not be a terminal.  Shells are interactive without
           this option if their inputs and outputs are terminals.

       -l  The shell is a login shell.  Applicable only if -l is the only flag

       -m  The  shell loads ~/.tcshrc even if it does not belong to the effec-
           tive user.  Newer versions of su(1) can pass -m to the shell. (+)

       -n  The shell parses commands but does not execute them.  This aids  in
           debugging shell scripts.

       -q  The shell accepts SIGQUIT (see Signal handling) and behaves when it
           is used under a debugger.  Job control is disabled. (u)

       -s  Command input is taken from the standard input.

       -t  The shell reads and executes a single line of input.  A `\' may  be
           used  to  escape  the  newline at the end of this line and continue
           onto another line.

       -v  Sets the verbose shell variable, so that command  input  is  echoed
           after history substitution.

       -x  Sets  the  echo shell variable, so that commands are echoed immedi-
           ately before execution.

       -V  Sets the verbose shell variable even before executing ~/.tcshrc.

       -X  Is to -x as -V is to -v.

           Print a help message on the standard output and exit. (+)

           Print the version/platform/compilation options on the standard out-
           put  and  exit.   This information is also contained in the version
           shell variable. (+)

       After processing of flag arguments, if arguments remain but none of the
       -c,  -i,  -s,  or -t options were given, the first argument is taken as
       the name of a file of commands, or ``script'',  to  be  executed.   The
       shell opens this file and saves its name for possible resubstitution by
       `$0'.  Because many systems use either the standard version 6  or  ver-
       sion  7  shells whose shell scripts are not compatible with this shell,
       the shell uses such a `standard' shell to execute a script whose  first
       character is not a `#', i.e., that does not start with a comment.

       Remaining arguments are placed in the argv shell variable.

   Startup and shutdown
       A  login  shell  begins  by  executing  commands  from the system files
       /etc/csh.cshrc and /etc/csh.login.   It  then  executes  commands  from
       files  in  the  user's  home  directory:  first  ~/.tcshrc  (+)  or, if
       ~/.tcshrc is not found, ~/.cshrc, then ~/.history (or the value of  the
       histfile shell variable), then ~/.login, and finally ~/.cshdirs (or the
       value of  the  dirsfile  shell  variable)  (+).   The  shell  may  read
       /etc/csh.login  before  instead  of  after /etc/csh.cshrc, and ~/.login
       before instead of after ~/.tcshrc or ~/.cshrc  and  ~/.history,  if  so
       compiled; see the version shell variable. (+)

       Non-login  shells read only /etc/csh.cshrc and ~/.tcshrc or ~/.cshrc on

       For examples of startup  files,  please  consult  http://tcshrc.source-

       Commands  like  stty(1)  and  tset(1),  which need be run only once per
       login, usually go in one's ~/.login file.  Users who need  to  use  the
       same  set  of  files with both csh(1) and tcsh can have only a ~/.cshrc
       which checks for the existence of the tcsh shell variable (q.v.) before
       using  tcsh-specific  commands,  or  can  have  both  a  ~/.cshrc and a
       ~/.tcshrc which sources (see the builtin command) ~/.cshrc.   The  rest
       of  this manual uses `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is
       not found, ~/.cshrc'.

       In the normal case, the shell begins reading commands from  the  termi-
       nal,  prompting with `> '.  (Processing of arguments and the use of the
       shell to process files containing command scripts are described later.)
       The  shell  repeatedly  reads  a  line of command input, breaks it into
       words, places it on the command history list, parses  it  and  executes
       each command in the line.

       One can log out by typing `^D' on an empty line, `logout' or `login' or
       via the shell's autologout mechanism (see the  autologout  shell  vari-
       able).  When a login shell terminates it sets the logout shell variable
       to `normal' or `automatic' as appropriate, then executes commands  from
       the  files  /etc/csh.logout  and  ~/.logout.  The shell may drop DTR on
       logout if so compiled; see the version shell variable.

       The names of the system login and logout files vary from system to sys-
       tem for compatibility with different csh(1) variants; see FILES.

       We  first describe The command-line editor.  The Completion and listing
       and Spelling correction sections describe  two  sets  of  functionality
       that  are  implemented  as  editor commands but which deserve their own
       treatment.  Finally, Editor commands lists  and  describes  the  editor
       commands specific to the shell and their default bindings.

   The command-line editor (+)
       Command-line  input  can  be edited using key sequences much like those
       used in GNU Emacs or vi(1).  The editor is active only  when  the  edit
       shell  variable  is  set, which it is by default in interactive shells.
       The bindkey builtin can display and change key  bindings.   Emacs-style
       key  bindings are used by default (unless the shell was compiled other-
       wise; see the version shell variable), but bindkey can change  the  key
       bindings to vi-style bindings en masse.

       The  shell always binds the arrow keys (as defined in the TERMCAP envi-
       ronment variable) to

           down    down-history
           up      up-history
           left    backward-char
           right   forward-char

       unless doing so would alter another single-character binding.  One  can
       set  the  arrow  key escape sequences to the empty string with settc to
       prevent these bindings.  The ANSI/VT100 sequences for  arrow  keys  are
       always bound.

       Other  key  bindings are, for the most part, what Emacs and vi(1) users
       would expect and can easily be displayed by bindkey,  so  there  is  no
       need to list them here.  Likewise, bindkey can list the editor commands
       with a short description of each.

       Note that editor commands do not have the same notion of a ``word''  as
       does  the  shell.   The editor delimits words with any non-alphanumeric
       characters not in the shell variable wordchars, while the shell  recog-
       nizes  only whitespace and some of the characters with special meanings
       to it, listed under Lexical structure.

   Completion and listing (+)
       The shell is often able to complete words when given a unique abbrevia-
       tion.  Type part of a word (for example `ls /usr/lost') and hit the tab
       key to run the complete-word editor command.  The shell  completes  the
       filename  `/usr/lost'  to  `/usr/lost+found/', replacing the incomplete
       word with the complete word in the input buffer.   (Note  the  terminal
       `/';  completion  adds  a `/' to the end of completed directories and a
       space to the end of other completed words, to speed typing and  provide
       a visual indicator of successful completion.  The addsuffix shell vari-
       able can be unset to prevent this.)  If  no  match  is  found  (perhaps
       `/usr/lost+found' doesn't exist), the terminal bell rings.  If the word
       is already complete (perhaps there is a `/usr/lost' on your system,  or
       perhaps  you  were  thinking too far ahead and typed the whole thing) a
       `/' or space is added to the end if it isn't already there.

       Completion works anywhere in the line, not at just the  end;  completed
       text  pushes the rest of the line to the right.  Completion in the mid-
       dle of a word often results in leftover characters to the right of  the
       cursor that need to be deleted.

       Commands  and  variables  can  be  completed in much the same way.  For
       example, typing `em[tab]' would complete `em' to `emacs' if emacs  were
       the  only  command  on your system beginning with `em'.  Completion can
       find a command in any directory in path or if given  a  full  pathname.
       Typing  `echo  $ar[tab]'  would  complete  `$ar' to `$argv' if no other
       variable began with `ar'.

       The shell parses the input buffer to determine  whether  the  word  you
       want  to  complete  should be completed as a filename, command or vari-
       able.  The first word in the buffer and the first word  following  `;',
       `|',  `|&',  `&&' or `||' is considered to be a command.  A word begin-
       ning with `$' is considered to be a variable.  Anything else is a file-
       name.  An empty line is `completed' as a filename.

       You  can  list the possible completions of a word at any time by typing
       `^D' to run the delete-char-or-list-or-eof editor command.   The  shell
       lists  the  possible completions using the ls-F builtin (q.v.)  and re-
       prints the prompt and unfinished command line, for example:

           > ls /usr/l[^D]
           lbin/       lib/        local/      lost+found/
           > ls /usr/l

       If the autolist shell variable is set, the shell  lists  the  remaining
       choices (if any) whenever completion fails:

           > set autolist
           > nm /usr/lib/libt[tab]
           libtermcap.a@ libtermlib.a@
           > nm /usr/lib/libterm

       If autolist is set to `ambiguous', choices are listed only when comple-
       tion fails and adds no new characters to the word being completed.

       A filename to be completed can contain variables, your own  or  others'
       home  directories  abbreviated with `~' (see Filename substitution) and
       directory stack entries abbreviated with `=' (see Directory stack  sub-
       stitution).  For example,

           > ls ~k[^D]
           kahn    kas     kellogg
           > ls ~ke[tab]
           > ls ~kellogg/


           > set local = /usr/local
           > ls $lo[tab]
           > ls $local/[^D]
           bin/ etc/ lib/ man/ src/
           > ls $local/

       Note  that  variables  can also be expanded explicitly with the expand-
       variables editor command.

       delete-char-or-list-or-eof lists at only the end of the  line;  in  the
       middle  of  a  line it deletes the character under the cursor and on an
       empty line it logs one out or,  if  ignoreeof  is  set,  does  nothing.
       `M-^D', bound to the editor command list-choices, lists completion pos-
       sibilities anywhere on a line, and list-choices  (or  any  one  of  the
       related  editor  commands that do or don't delete, list and/or log out,
       listed under delete-char-or-list-or-eof) can be bound to `^D' with  the
       bindkey builtin command if so desired.

       The complete-word-fwd and complete-word-back editor commands (not bound
       to any keys by default) can be used to cycle up and  down  through  the
       list  of possible completions, replacing the current word with the next
       or previous word in the list.

       The shell variable fignore can be set to  a  list  of  suffixes  to  be
       ignored by completion.  Consider the following:

           > ls
           Makefile        condiments.h~   main.o          side.c
           README          main.c          meal            side.o
           condiments.h    main.c~
           > set fignore = (.o \~)
           > emacs ma[^D]
           main.c   main.c~  main.o
           > emacs ma[tab]
           > emacs main.c

       `main.c~'  and  `main.o'  are  ignored by completion (but not listing),
       because they end in suffixes in fignore.  Note that a `\' was needed in
       front  of  `~'  to  prevent it from being expanded to home as described
       under Filename substitution.  fignore is ignored if only one completion
       is possible.

       If  the  complete  shell  variable  is  set to `enhance', completion 1)
       ignores case and 2) considers periods, hyphens  and  underscores  (`.',
       `-'  and  `_')  to be word separators and hyphens and underscores to be
       equivalent.  If you had the following files

           comp.lang.c      comp.lang.perl   comp.std.c++
           comp.lang.c++    comp.std.c

       and typed `mail -f c.l.c[tab]', it  would  be  completed  to  `mail  -f
       comp.lang.c',  and  ^D  would  list  `comp.lang.c' and `comp.lang.c++'.
       `mail -f c..c++[^D]' would  list  `comp.lang.c++'  and  `comp.std.c++'.
       Typing `rm a--file[^D]' in the following directory

           A_silly_file    a-hyphenated-file    another_silly_file

       would  list  all  three  files, because case is ignored and hyphens and
       underscores are equivalent.  Periods, however, are  not  equivalent  to
       hyphens or underscores.

       Completion  and  listing are affected by several other shell variables:
       recexact can be set to complete on the shortest possible unique  match,
       even if more typing might result in a longer match:

           > ls
           fodder   foo      food     foonly
           > set recexact
           > rm fo[tab]

       just beeps, because `fo' could expand to `fod' or `foo', but if we type
       another `o',

           > rm foo[tab]
           > rm foo

       the completion completes on `foo', even though `food' and `foonly' also
       match.   autoexpand can be set to run the expand-history editor command
       before each completion attempt, autocorrect can be set to spelling-cor-
       rect  the  word  to  be completed (see Spelling correction) before each
       completion attempt and correct can be set to complete commands automat-
       ically  after  one hits `return'.  matchbeep can be set to make comple-
       tion beep or not beep in a variety of situations, and nobeep can be set
       to  never  beep  at  all.   nostat  can be set to a list of directories
       and/or patterns that match directories to prevent the completion mecha-
       nism from stat(2)ing those directories.  listmax and listmaxrows can be
       set to limit the number of  items  and  rows  (respectively)  that  are
       listed  without asking first.  recognize_only_executables can be set to
       make the shell list only executables when listing commands, but  it  is
       quite slow.

       Finally, the complete builtin command can be used to tell the shell how
       to complete words other than filenames, commands and  variables.   Com-
       pletion  and listing do not work on glob-patterns (see Filename substi-
       tution), but the list-glob  and  expand-glob  editor  commands  perform
       equivalent functions for glob-patterns.

   Spelling correction (+)
       The shell can sometimes correct the spelling of filenames, commands and
       variable names as well as completing and listing them.

       Individual words can be spelling-corrected with the  spell-word  editor
       command (usually bound to M-s and M-S) and the entire input buffer with
       spell-line (usually bound to M-$).  The correct shell variable  can  be
       set to `cmd' to correct the command name or `all' to correct the entire
       line each time return is typed, and autocorrect can be set  to  correct
       the word to be completed before each completion attempt.

       When  spelling correction is invoked in any of these ways and the shell
       thinks that any part of the command line is misspelled, it prompts with
       the corrected line:

           > set correct = cmd
           > lz /usr/bin
           CORRECT>ls /usr/bin (y|n|e|a)?

       One can answer `y' or space to execute the corrected line, `e' to leave
       the uncorrected command in the input buffer, `a' to abort  the  command
       as if `^C' had been hit, and anything else to execute the original line

       Spelling correction recognizes user-defined completions (see  the  com-
       plete  builtin  command).   If  an input word in a position for which a
       completion is defined resembles a word in the completion list, spelling
       correction  registers  a  misspelling and suggests the latter word as a
       correction.  However, if the input word does not match any of the  pos-
       sible  completions for that position, spelling correction does not reg-
       ister a misspelling.

       Like completion, spelling correction works anywhere in the line,  push-
       ing  the rest of the line to the right and possibly leaving extra char-
       acters to the right of the cursor.

       Beware: spelling correction is not  guaranteed  to  work  the  way  one
       intends,  and  is  provided mostly as an experimental feature.  Sugges-
       tions and improvements are welcome.

   Editor commands (+)
       `bindkey' lists  key  bindings  and  `bindkey  -l'  lists  and  briefly
       describes  editor  commands.  Only new or especially interesting editor
       commands are described here.  See emacs(1) and vi(1)  for  descriptions
       of each editor's key bindings.

       The  character  or characters to which each command is bound by default
       is given in parentheses.  `^character' means a  control  character  and
       `M-character'  a meta character, typed as escape-character on terminals
       without a meta key.  Case counts, but commands that are bound  to  let-
       ters by default are bound to both lower- and uppercase letters for con-

       complete-word (tab)
               Completes a word as described under Completion and listing.

       complete-word-back (not bound)
               Like complete-word-fwd, but steps up from the end of the  list.

       complete-word-fwd (not bound)
               Replaces  the  current  word with the first word in the list of
               possible completions.  May be repeated to step down through the
               list.   At the end of the list, beeps and reverts to the incom-
               plete word.

       complete-word-raw (^X-tab)
               Like complete-word, but ignores user-defined completions.

       copy-prev-word (M-^_)
               Copies the previous word in the current  line  into  the  input
               buffer.  See also insert-last-word.

       dabbrev-expand (M-/)
               Expands  the  current word to the most recent preceding one for
               which the current is a leading substring, wrapping  around  the
               history  list  (once)  if  necessary.  Repeating dabbrev-expand
               without any intervening typing changes  to  the  next  previous
               word etc., skipping identical matches much like history-search-
               backward does.

       delete-char (not bound)
               Deletes the character under the cursor.  See also  delete-char-

       delete-char-or-eof (not bound)
               Does  delete-char  if  there is a character under the cursor or
               end-of-file on an empty line.  See also delete-char-or-list-or-

       delete-char-or-list (not bound)
               Does  delete-char  if  there is a character under the cursor or
               list-choices at the end of the line.  See also  delete-char-or-

       delete-char-or-list-or-eof (^D)
               Does  delete-char  if  there  is  a character under the cursor,
               list-choices at the end of the line or end-of-file on an  empty
               line.  See also those three commands, each of which does only a
               single action, and delete-char-or-eof, delete-char-or-list  and
               list-or-eof,  each  of  which  does  a different two out of the

       down-history (down-arrow, ^N)
               Like up-history, but steps down, stopping at the original input

       end-of-file (not bound)
               Signals  an  end  of file, causing the shell to exit unless the
               ignoreeof shell variable (q.v.) is set to  prevent  this.   See
               also delete-char-or-list-or-eof.

       expand-history (M-space)
               Expands history substitutions in the current word.  See History
               substitution.  See also magic-space, toggle-literal-history and
               the autoexpand shell variable.

       expand-glob (^X-*)
               Expands  the glob-pattern to the left of the cursor.  See File-
               name substitution.

       expand-line (not bound)
               Like expand-history, but expands history substitutions in  each
               word in the input buffer,

       expand-variables (^X-$)
               Expands  the  variable to the left of the cursor.  See Variable

       history-search-backward (M-p, M-P)
               Searches backwards through  the  history  list  for  a  command
               beginning  with  the current contents of the input buffer up to
               the cursor and copies it into the  input  buffer.   The  search
               string  may  be a glob-pattern (see Filename substitution) con-
               taining `*', `?', `[]' or `{}'.   up-history  and  down-history
               will  proceed  from  the appropriate point in the history list.
               Emacs mode only.  See also history-search-forward and i-search-

       history-search-forward (M-n, M-N)
               Like history-search-backward, but searches forward.

       i-search-back (not bound)
               Searches  backward  like  history-search-backward,  copies  the
               first match into the input buffer with the cursor positioned at
               the  end of the pattern, and prompts with `bck: ' and the first
               match.  Additional  characters  may  be  typed  to  extend  the
               search,  i-search-back  may be typed to continue searching with
               the same pattern, wrapping around the history  list  if  neces-
               sary,  (i-search-back  must  be bound to a single character for
               this to work) or one of the following special characters may be

                   ^W      Appends  the  rest  of the word under the cursor to
                           the search pattern.
                   delete (or any character bound to backward-delete-char)
                           Undoes the effect of the last character  typed  and
                           deletes  a  character  from  the  search pattern if
                   ^G      If the previous search was successful,  aborts  the
                           entire  search.  If not, goes back to the last suc-
                           cessful search.
                   escape  Ends the search, leaving the current  line  in  the
                           input buffer.

               Any other character not bound to self-insert-command terminates
               the search, leaving the current line in the input  buffer,  and
               is then interpreted as normal input.  In particular, a carriage
               return causes the current line  to  be  executed.   Emacs  mode
               only.  See also i-search-fwd and history-search-backward.

       i-search-fwd (not bound)
               Like i-search-back, but searches forward.

       insert-last-word (M-_)
               Inserts  the  last  word of the previous input line (`!$') into
               the input buffer.  See also copy-prev-word.

       list-choices (M-^D)
               Lists completion possibilities as  described  under  Completion
               and  listing.   See  also  delete-char-or-list-or-eof and list-

       list-choices-raw (^X-^D)
               Like list-choices, but ignores user-defined completions.

       list-glob (^X-g, ^X-G)
               Lists (via the ls-F builtin) matches to the  glob-pattern  (see
               Filename substitution) to the left of the cursor.

       list-or-eof (not bound)
               Does  list-choices  or  end-of-file on an empty line.  See also

       magic-space (not bound)
               Expands history substitutions in the current line, like expand-
               history,  and  inserts  a space.  magic-space is designed to be
               bound to the space bar, but is not bound by default.

       normalize-command (^X-?)
               Searches for the current word in PATH  and,  if  it  is  found,
               replaces  it  with  the  full  path to the executable.  Special
               characters are quoted.  Aliases are  expanded  and  quoted  but
               commands  within  aliases are not.  This command is useful with
               commands that take commands as arguments, e.g., `dbx'  and  `sh

       normalize-path (^X-n, ^X-N)
               Expands  the  current word as described under the `expand' set-
               ting of the symlinks shell variable.

       overwrite-mode (unbound)
               Toggles between input and overwrite modes.

       run-fg-editor (M-^Z)
               Saves the current input line and looks for a stopped job with a
               name  equal  to the last component of the file name part of the
               EDITOR or VISUAL environment variables, or, if neither is  set,
               `ed'  or  `vi'.   If such a job is found, it is restarted as if
               `fg %job' had been typed.  This is  used  to  toggle  back  and
               forth between an editor and the shell easily.  Some people bind
               this command to `^Z' so they can do this even more easily.

       run-help (M-h, M-H)
               Searches for documentation on the current  command,  using  the
               same  notion  of  `current command' as the completion routines,
               and prints it.  There is no way to use  a  pager;  run-help  is
               designed  for  short help files.  If the special alias helpcom-
               mand is defined, it is run with the  command  name  as  a  sole
               argument.   Else,  documentation should be in a file named com-
     , command.1, command.6, command.8  or  command,  which
               should  be  in one of the directories listed in the HPATH envi-
               ronment variable.  If there is more than one help file only the
               first is printed.

       self-insert-command (text characters)
               In  insert mode (the default), inserts the typed character into
               the input line after the character under the cursor.  In  over-
               write  mode,  replaces  the character under the cursor with the
               typed character.  The input mode is normally preserved  between
               lines,  but the inputmode shell variable can be set to `insert'
               or `overwrite' to put the editor in that mode at the  beginning
               of each line.  See also overwrite-mode.

       sequence-lead-in (arrow prefix, meta prefix, ^X)
               Indicates that the following characters are part of a multi-key
               sequence.  Binding a command to  a  multi-key  sequence  really
               creates  two  bindings: the first character to sequence-lead-in
               and the whole sequence to the command.  All sequences beginning
               with  a  character  bound  to  sequence-lead-in are effectively
               bound to undefined-key unless bound to another command.

       spell-line (M-$)
               Attempts to correct the spelling of  each  word  in  the  input
               buffer,  like spell-word, but ignores words whose first charac-
               ter is one of `-', `!', `^' or `%', or which contain  `\',  `*'
               or  `?', to avoid problems with switches, substitutions and the
               like.  See Spelling correction.

       spell-word (M-s, M-S)
               Attempts to  correct  the  spelling  of  the  current  word  as
               described  under Spelling correction.  Checks each component of
               a word which appears to be a pathname.

       toggle-literal-history (M-r, M-R)
               Expands or  `unexpands'  history  substitutions  in  the  input
               buffer.  See also expand-history and the autoexpand shell vari-

       undefined-key (any unbound key)

       up-history (up-arrow, ^P)
               Copies the previous entry in the history list  into  the  input
               buffer.  If histlit is set, uses the literal form of the entry.
               May be repeated to step up through the history  list,  stopping
               at the top.

       vi-search-back (?)
               Prompts  with `?' for a search string (which may be a glob-pat-
               tern, as with history-search-backward),  searches  for  it  and
               copies it into the input buffer.  The bell rings if no match is
               found.  Hitting return ends the  search  and  leaves  the  last
               match  in the input buffer.  Hitting escape ends the search and
               executes the match.  vi mode only.

       vi-search-fwd (/)
               Like vi-search-back, but searches forward.

       which-command (M-?)
               Does a which (see the description of the  builtin  command)  on
               the first word of the input buffer.

       yank-pop (M-y)
               When  executed  immediately  after  a yank or another yank-pop,
               replaces the yanked string with the next previous  string  from
               the  killring.  This  also has the effect of rotating the kill-
               ring, such  that  this  string  will  be  considered  the  most
               recently  killed  by  a  later yank command. Repeating yank-pop
               will cycle through the killring any number of times.

   Lexical structure
       The shell splits input lines into words at blanks and tabs.   The  spe-
       cial  characters  `&', `|', `;', `<', `>', `(', and `)' and the doubled
       characters `&&', `||', `<<' and `>>' are always separate words, whether
       or not they are surrounded by whitespace.

       When the shell's input is not a terminal, the character `#' is taken to
       begin a comment.  Each `#' and the rest of the input line on  which  it
       appears is discarded before further parsing.

       A  special  character  (including a blank or tab) may be prevented from
       having its special meaning, and possibly made part of another word,  by
       preceding  it  with  a backslash (`\') or enclosing it in single (`''),
       double (`"') or backward (``') quotes.  When  not  otherwise  quoted  a
       newline  preceded  by a `\' is equivalent to a blank, but inside quotes
       this sequence results in a newline.

       Furthermore, all Substitutions (see below) except History  substitution
       can  be  prevented  by  enclosing  the strings (or parts of strings) in
       which they appear with single quotes or by quoting the crucial  charac-
       ter(s) (e.g., `$' or ``' for Variable substitution or Command substitu-
       tion respectively) with `\'.   (Alias  substitution  is  no  exception:
       quoting  in any way any character of a word for which an alias has been
       defined prevents substitution of the alias.  The usual way  of  quoting
       an  alias  is  to precede it with a backslash.) History substitution is
       prevented by backslashes but not by single quotes.  Strings quoted with
       double  or  backward  quotes  undergo Variable substitution and Command
       substitution, but other substitutions are prevented.

       Text inside single or double quotes becomes a single word (or  part  of
       one).   Metacharacters  in these strings, including blanks and tabs, do
       not form separate words.  Only in one special case (see Command substi-
       tution  below)  can a double-quoted string yield parts of more than one
       word; single-quoted strings never do.   Backward  quotes  are  special:
       they  signal Command substitution (q.v.), which may result in more than
       one word.

       Quoting complex strings, particularly strings which themselves  contain
       quoting characters, can be confusing.  Remember that quotes need not be
       used as they are in human writing!  It may be easier to  quote  not  an
       entire  string,  but only those parts of the string which need quoting,
       using different types of quoting to do so if appropriate.

       The backslash_quote shell variable (q.v.) can  be  set  to  make  back-
       slashes  always  quote  `\',  `'',  and `"'.  (+) This may make complex
       quoting tasks easier, but it can cause syntax errors in csh(1) scripts.

       We  now  describe the various transformations the shell performs on the
       input in the order in which they occur.  We note in  passing  the  data
       structures  involved  and the commands and variables which affect them.
       Remember that substitutions can be prevented by  quoting  as  described
       under Lexical structure.

   History substitution
       Each  command,  or  ``event'',  input from the terminal is saved in the
       history list.  The previous command is always saved,  and  the  history
       shell  variable can be set to a number to save that many commands.  The
       histdup shell variable can be set to not save duplicate events or  con-
       secutive duplicate events.

       Saved  commands  are  numbered sequentially from 1 and stamped with the
       time.  It is not usually necessary to use event numbers, but  the  cur-
       rent  event  number can be made part of the prompt by placing an `!' in
       the prompt shell variable.

       The shell actually saves history in expanded and  literal  (unexpanded)
       forms.  If the histlit shell variable is set, commands that display and
       store history use the literal form.

       The history builtin command can print, store in  a  file,  restore  and
       clear the history list at any time, and the savehist and histfile shell
       variables can be can be set to store the history list automatically  on
       logout and restore it on login.

       History  substitutions  introduce  words from the history list into the
       input stream, making it easy to repeat commands, repeat arguments of  a
       previous  command  in  the current command, or fix spelling mistakes in
       the previous command with little typing and a  high  degree  of  confi-

       History  substitutions  begin  with  the character `!'.  They may begin
       anywhere in the input stream, but they do not nest.   The  `!'  may  be
       preceded  by  a  `\' to prevent its special meaning; for convenience, a
       `!' is passed unchanged when it is followed by a blank,  tab,  newline,
       `=' or `('.  History substitutions also occur when an input line begins
       with `^'.  This special abbreviation  will  be  described  later.   The
       characters  used  to  signal  history substitution (`!' and `^') can be
       changed by setting the histchars shell variable.  Any input line  which
       contains a history substitution is printed before it is executed.

       A history substitution may have an ``event specification'', which indi-
       cates the event from which words are to be  taken,  a  ``word  designa-
       tor'',  which  selects particular words from the chosen event, and/or a
       ``modifier'', which manipulates the selected words.

       An event specification can be

           n       A number, referring to a particular event
           -n      An offset, referring to the  event  n  before  the  current
           #       The  current  event.   This  should  be  used  carefully in
                   csh(1), where there is no check for recursion.  tcsh allows
                   10 levels of recursion.  (+)
           !       The previous event (equivalent to `-1')
           s       The  most  recent  event  whose  first word begins with the
                   string s
           ?s?     The most recent event which contains  the  string  s.   The
                   second  `?' can be omitted if it is immediately followed by
                   a newline.

       For example, consider this bit of someone's history list:

            9  8:30    nroff -man
           10  8:31    cp
           11  8:36    vi
           12  8:37    diff

       The commands are shown with their event numbers and time  stamps.   The
       current  event,  which we haven't typed in yet, is event 13.  `!11' and
       `!-2' refer to event 11.  `!!' refers to the previous event, 12.   `!!'
       can  be  abbreviated  `!'  if  it  is followed by `:' (`:' is described
       below).  `!n' refers to event 9, which begins with `n'.  `!?old?'  also
       refers  to event 12, which contains `old'.  Without word designators or
       modifiers history references simply expand to the entire event,  so  we
       might  type  `!cp'  to redo the copy command or `!!|more' if the `diff'
       output scrolled off the top of the screen.

       History references may be insulated  from  the  surrounding  text  with
       braces  if  necessary.   For  example, `!vdoc' would look for a command
       beginning with  `vdoc',  and,  in  this  example,  not  find  one,  but
       `!{v}doc'  would  expand  unambiguously to `vi wumpus.mandoc'.  Even in
       braces, history substitutions do not nest.

       (+) While csh(1) expands, for example, `!3d' to event 3 with the letter
       `d'  appended  to  it, tcsh expands it to the last event beginning with
       `3d'; only completely numeric arguments are treated as  event  numbers.
       This  makes  it  possible  to recall events beginning with numbers.  To
       expand `!3d' as in csh(1) say `!{3}d'.

       To select words from an event we can follow the event specification  by
       a  `:'  and  a designator for the desired words.  The words of an input
       line are numbered from 0, the first (usually command) word being 0, the
       second  word (first argument) being 1, etc.  The basic word designators

           0       The first (command) word
           n       The nth argument
           ^       The first argument, equivalent to `1'
           $       The last argument
           %       The word matched by an ?s? search
           x-y     A range of words
           -y      Equivalent to `0-y'
           *       Equivalent to `^-$', but returns nothing if the event  con-
                   tains only 1 word
           x*      Equivalent to `x-$'
           x-      Equivalent to `x*', but omitting the last word (`$')

       Selected  words  are inserted into the command line separated by single
       blanks.  For example, the `diff' command in the previous example  might
       have been typed as `diff !!:1.old !!:1' (using `:1' to select the first
       argument from the previous event) or `diff !-2:2 !-2:1' to  select  and
       swap  the arguments from the `cp' command.  If we didn't care about the
       order of the `diff' we might have said `diff !-2:1-2' or  simply  `diff
       !-2:*'.   The  `cp'  command  might  have  been  written `cp
       !#:1.old', using `#' to refer to the current event.  `!n:-'
       would  reuse the first two words from the `nroff' command to say `nroff

       The `:' separating the event specification from the word designator can
       be omitted if the argument selector begins with a `^', `$', `*', `%' or
       `-'.  For example, our `diff' command might  have  been  `diff  !!^.old
       !!^'  or, equivalently, `diff !!$.old !!$'.  However, if `!!' is abbre-
       viated `!', an argument selector beginning with `-' will be interpreted
       as an event specification.

       A  history reference may have a word designator but no event specifica-
       tion.  It then references the previous command.  Continuing our  `diff'
       example,  we  could  have  said  simply `diff !^.old !^' or, to get the
       arguments in the opposite order, just `diff !*'.

       The word or words in a history reference  can  be  edited,  or  ``modi-
       fied'',  by following it with one or more modifiers, each preceded by a

           h       Remove a trailing pathname component, leaving the head.
           t       Remove all leading pathname components, leaving the tail.
           r       Remove a filename extension `.xxx', leaving the root  name.
           e       Remove all but the extension.
           u       Uppercase the first lowercase letter.
           l       Lowercase the first uppercase letter.
           s/l/r/  Substitute  l  for  r.   l is simply a string like r, not a
                   regular expression as in the eponymous ed(1) command.   Any
                   character  may  be used as the delimiter in place of `/'; a
                   `\' can be used to quote the delimiter inside l and r.  The
                   character  `&'  in  the r is replaced by l; `\' also quotes
                   `&'.  If l is empty (``''), the l from a previous substitu-
                   tion  or  the  s  from a previous search or event number in
                   event specification is used.  The trailing delimiter may be
                   omitted if it is immediately followed by a newline.
           &       Repeat the previous substitution.
           g       Apply the following modifier once to each word.
           a (+)   Apply the following modifier as many times as possible to a
                   single word.  `a' and `g' can be used together to  apply  a
                   modifier  globally.   With  the `s' modifier, only the pat-
                   terns contained in the original word are  substituted,  not
                   patterns that contain any substitution result.
           p       Print the new command line but do not execute it.
           q       Quote  the  substituted words, preventing further substitu-
           x       Like q, but break into words at blanks, tabs and  newlines.

       Modifiers  are applied to only the first modifiable word (unless `g' is
       used).  It is an error for no word to be modifiable.

       For example, the `diff' command might have been written as  `diff  wum- !#^:r', using `:r' to remove `.old' from the first argument
       on the same line (`!#^').  We could say `echo hello  out  there',  then
       `echo  !*:u' to capitalize `hello', `echo !*:au' to say it out loud, or
       `echo !*:agu' to really shout.  We might follow `mail -s "I  forgot  my
       password"  rot'  with  `!:s/rot/root' to correct the spelling of `root'
       (but see Spelling correction for a different approach).

       There is a special abbreviation for substitutions.  `^', when it is the
       first  character  on  an  input line, is equivalent to `!:s^'.  Thus we
       might have said `^rot^root' to make the spelling correction in the pre-
       vious  example.   This  is the only history substitution which does not
       explicitly begin with `!'.

       (+) In csh as such, only one modifier may be applied to each history or
       variable expansion.  In tcsh, more than one may be used, for example

           % mv /usr/man/man1/wumpus.1
           % man !$:t:r
           man wumpus

       In csh, the result would be `wumpus.1:r'.  A substitution followed by a
       colon may need to be insulated from it with braces:

           > mv a.out /usr/games/wumpus
           > setenv PATH !$:h:$PATH
           Bad ! modifier: $.
           > setenv PATH !{-2$:h}:$PATH
           setenv PATH /usr/games:/bin:/usr/bin:.

       The first attempt would succeed in csh but fails in tcsh, because  tcsh
       expects another modifier after the second colon rather than `$'.

       Finally,  history can be accessed through the editor as well as through
       the substitutions just described.  The up- and  down-history,  history-
       search-backward  and  -forward,  i-search-back and -fwd, vi-search-back
       and -fwd, copy-prev-word and insert-last-word  editor  commands  search
       for  events  in  the  history list and copy them into the input buffer.
       The toggle-literal-history editor command switches between the expanded
       and literal forms of history lines in the input buffer.  expand-history
       and expand-line expand history substitutions in the current word and in
       the entire input buffer respectively.

   Alias substitution
       The  shell  maintains  a  list  of  aliases which can be set, unset and
       printed by the alias and unalias commands.  After  a  command  line  is
       parsed  into simple commands (see Commands) the first word of each com-
       mand, left-to-right, is checked to see if it has an alias.  If so,  the
       first  word  is replaced by the alias.  If the alias contains a history
       reference, it undergoes History substitution (q.v.) as though the orig-
       inal  command were the previous input line.  If the alias does not con-
       tain a history reference, the argument list is left untouched.

       Thus if the alias for `ls' were `ls -l' the  command  `ls  /usr'  would
       become  `ls -l /usr', the argument list here being undisturbed.  If the
       alias for `lookup' were `grep !^ /etc/passwd' then `lookup bill'  would
       become  `grep  bill  /etc/passwd'.   Aliases  can  be used to introduce
       parser metasyntax.  For example, `alias print 'pr \!* | lpr'' defines a
       ``command'' (`print') which pr(1)s its arguments to the line printer.

       Alias  substitution is repeated until the first word of the command has
       no alias.  If an alias substitution does not change the first word  (as
       in  the previous example) it is flagged to prevent a loop.  Other loops
       are detected and cause an error.

       Some aliases are referred to by the shell; see Special aliases.

   Variable substitution
       The shell maintains a list of variables, each of which has as  value  a
       list  of zero or more words.  The values of shell variables can be dis-
       played and changed with the set and unset commands.  The  system  main-
       tains  its  own  list  of ``environment'' variables.  These can be dis-
       played and changed with printenv, setenv and unsetenv.

       (+) Variables may be made read-only with  `set  -r'  (q.v.)   Read-only
       variables  may not be modified or unset; attempting to do so will cause
       an error.  Once made read-only, a variable cannot be made writable,  so
       `set  -r' should be used with caution.  Environment variables cannot be
       made read-only.

       Some variables are set  by  the  shell  or  referred  to  by  it.   For
       instance,  the  argv variable is an image of the shell's argument list,
       and words of this variable's value are referred  to  in  special  ways.
       Some  of  the variables referred to by the shell are toggles; the shell
       does not care what their value is, only whether they are  set  or  not.
       For  instance,  the  verbose  variable is a toggle which causes command
       input to be echoed.  The -v command line  option  sets  this  variable.
       Special  shell  variables  lists all variables which are referred to by
       the shell.

       Other operations treat variables numerically.  The `@' command  permits
       numeric calculations to be performed and the result assigned to a vari-
       able.  Variable values are, however, always  represented  as  (zero  or
       more) strings.  For the purposes of numeric operations, the null string
       is considered to be zero, and the second and subsequent words of multi-
       word values are ignored.

       After  the input line is aliased and parsed, and before each command is
       executed, variable substitution is performed keyed by  `$'  characters.
       This  expansion can be prevented by preceding the `$' with a `\' except
       within `"'s where it always occurs, and  within  `''s  where  it  never
       occurs.   Strings quoted by ``' are interpreted later (see Command sub-
       stitution below) so `$' substitution does not occur there until  later,
       if  at  all.  A `$' is passed unchanged if followed by a blank, tab, or

       Input/output redirections are recognized before variable expansion, and
       are  variable  expanded  separately.   Otherwise,  the command name and
       entire argument list are expanded together.  It is  thus  possible  for
       the  first  (command)  word  (to  this point) to generate more than one
       word, the first of which becomes the command  name,  and  the  rest  of
       which become arguments.

       Unless  enclosed in `"' or given the `:q' modifier the results of vari-
       able substitution may eventually be command and  filename  substituted.
       Within  `"',  a variable whose value consists of multiple words expands
       to a (portion of a) single word, with the words of the variable's value
       separated  by blanks.  When the `:q' modifier is applied to a substitu-
       tion the variable will expand to multiple words with  each  word  sepa-
       rated  by  a blank and quoted to prevent later command or filename sub-

       The following metasequences are provided for introducing variable  val-
       ues into the shell input.  Except as noted, it is an error to reference
       a variable which is not set.

       ${name} Substitutes the words of the value of variable name, each sepa-
               rated  by a blank.  Braces insulate name from following charac-
               ters which would otherwise be part of it.  Shell variables have
               names  consisting of letters and digits starting with a letter.
               The underscore character is considered a letter.   If  name  is
               not  a shell variable, but is set in the environment, then that
               value is returned (but some of the other forms given below  are
               not available in this case).
               Substitutes  only  the  selected  words from the value of name.
               The selector is subjected to `$' substitution and  may  consist
               of  a  single  number  or  two numbers separated by a `-'.  The
               first word of a variable's value is numbered `1'.  If the first
               number  of  a range is omitted it defaults to `1'.  If the last
               member of a range is omitted  it  defaults  to  `$#name'.   The
               selector `*' selects all words.  It is not an error for a range
               to be empty if the second argument is omitted or in range.
       $0      Substitutes the name of the file from which  command  input  is
               being read.  An error occurs if the name is not known.
               Equivalent to `$argv[number]'.
       $*      Equivalent to `$argv', which is equivalent to `$argv[*]'.

       The  `:'  modifiers  described  under  History substitution, except for
       `:p', can be applied to the substitutions above.  More than one may  be
       used.   (+)  Braces  may  be needed to insulate a variable substitution
       from a literal colon just as with History substitution (q.v.); any mod-
       ifiers must appear within the braces.

       The following substitutions can not be modified with `:' modifiers.

               Substitutes the string `1' if name is set, `0' if it is not.
       $?0     Substitutes  `1' if the current input filename is known, `0' if
               it is not.  Always `0' in interactive shells.
               Substitutes the number of words in name.
       $#      Equivalent to `$#argv'.  (+)
               Substitutes the number of characters in name.  (+)
               Substitutes the number of characters in $argv[number].  (+)
       $?      Equivalent to `$status'.  (+)
       $$      Substitutes the (decimal) process number of the (parent) shell.
       $!      Substitutes the (decimal) process number of the last background
               process started by this shell.  (+)
       $_      Substitutes the command line of the last command executed.  (+)
       $<      Substitutes  a  line  from  the standard input, with no further
               interpretation thereafter.  It can be used  to  read  from  the
               keyboard in a shell script.  (+) While csh always quotes $<, as
               if it were equivalent to `$<:q', tcsh does  not.   Furthermore,
               when  tcsh  is waiting for a line to be typed the user may type
               an interrupt to interrupt the sequence into which the  line  is
               to be substituted, but csh does not allow this.

       The  editor  command expand-variables, normally bound to `^X-$', can be
       used to interactively expand individual variables.

   Command, filename and directory stack substitution
       The remaining substitutions are applied selectively to the arguments of
       builtin  commands.   This  means that portions of expressions which are
       not evaluated are not subjected  to  these  expansions.   For  commands
       which  are  not  internal to the shell, the command name is substituted
       separately from the argument list.  This occurs very late, after input-
       output redirection is performed, and in a child of the main shell.

   Command substitution
       Command  substitution  is  indicated by a command enclosed in ``'.  The
       output from such a command is broken into  separate  words  at  blanks,
       tabs  and  newlines, and null words are discarded.  The output is vari-
       able and command substituted and put in place of the original string.

       Command substitutions inside double  quotes  (`"')  retain  blanks  and
       tabs; only newlines force new words.  The single final newline does not
       force a new word in any case.  It is thus possible for a  command  sub-
       stitution  to  yield only part of a word, even if the command outputs a
       complete line.

       By default, the shell since version 6.12 replaces all newline and  car-
       riage  return characters in the command by spaces.  If this is switched
       off by unsetting csubstnonl, newlines separate commands as usual.

   Filename substitution
       If a word contains any of the characters `*', `?', `[' or `{' or begins
       with  the  character  `~'  it is a candidate for filename substitution,
       also known as ``globbing''.  This word is then regarded  as  a  pattern
       (``glob-pattern''),  and replaced with an alphabetically sorted list of
       file names which match the pattern.

       In matching filenames, the character `.' at the beginning of a filename
       or  immediately  following  a `/', as well as the character `/' must be
       matched explicitly.  The character `*' matches any  string  of  charac-
       ters,  including the null string.  The character `?' matches any single
       character.  The sequence `[...]' matches  any  one  of  the  characters
       enclosed.   Within  `[...]',  a  pair  of  characters  separated by `-'
       matches any character lexically between the two.

       (+) Some glob-patterns can be negated: The  sequence  `[^...]'  matches
       any  single  character not specified by the characters and/or ranges of
       characters in the braces.

       An entire glob-pattern can also be negated with `^':

           > echo *
           bang crash crunch ouch
           > echo ^cr*
           bang ouch

       Glob-patterns which do not use `?', `*', or `[]' or which use  `{}'  or
       `~' (below) are not negated correctly.

       The  metanotation  `a{b,c,d}e' is a shorthand for `abe ace ade'.  Left-
       to-right order is preserved: `/usr/source/s1/{oldls,ls}.c'  expands  to
       `/usr/source/s1/oldls.c  /usr/source/s1/ls.c'.   The results of matches
       are  sorted  separately  at  a  low  level  to  preserve  this   order:
       `../{memo,*box}'  might expand to `../memo ../box ../mbox'.  (Note that
       `memo' was not sorted with the results of matching `*box'.)  It is  not
       an  error  when this construct expands to files which do not exist, but
       it is possible to get an error from a command  to  which  the  expanded
       list  is  passed.  This construct may be nested.  As a special case the
       words `{', `}' and `{}' are passed undisturbed.

       The character `~' at the beginning of a filename refers to home  direc-
       tories.   Standing  alone,  i.e., `~', it expands to the invoker's home
       directory as reflected in the value of the home shell  variable.   When
       followed by a name consisting of letters, digits and `-' characters the
       shell searches for a user with that name  and  substitutes  their  home
       directory;  thus `~ken' might expand to `/usr/ken' and `~ken/chmach' to
       `/usr/ken/chmach'.  If the character `~' is  followed  by  a  character
       other  than  a letter or `/' or appears elsewhere than at the beginning
       of a word, it is left undisturbed.   A  command  like  `setenv  MANPATH
       /usr/man:/usr/local/man:~/lib/man'  does not, therefore, do home direc-
       tory substitution as one might hope.

       It is an error for a glob-pattern containing `*', `?', `[' or `~', with
       or without `^', not to match any files.  However, only one pattern in a
       list of glob-patterns must match a file (so that,  e.g.,  `rm  *.a  *.c
       *.o'  would  fail  only if there were no files in the current directory
       ending in `.a', `.c', or `.o'), and if the nonomatch shell variable  is
       set  a  pattern  (or  list  of  patterns) which matches nothing is left
       unchanged rather than causing an error.

       The noglob shell variable can be set to prevent filename  substitution,
       and  the  expand-glob  editor command, normally bound to `^X-*', can be
       used to interactively expand individual filename substitutions.

   Directory stack substitution (+)
       The directory stack is a list of directories, numbered from zero,  used
       by  the  pushd, popd and dirs builtin commands (q.v.).  dirs can print,
       store in a file, restore and clear the directory stack at any time, and
       the  savedirs  and  dirsfile  shell  variables  can be set to store the
       directory stack automatically on logout and restore it on  login.   The
       dirstack  shell variable can be examined to see the directory stack and
       set to put arbitrary directories into the directory stack.

       The character `=' followed by one or more digits expands to an entry in
       the  directory stack.  The special case `=-' expands to the last direc-
       tory in the stack.  For example,

           > dirs -v
           0       /usr/bin
           1       /usr/spool/uucp
           2       /usr/accts/sys
           > echo =1
           > echo =0/calendar
           > echo =-

       The noglob and nonomatch shell variables  and  the  expand-glob  editor
       command apply to directory stack as well as filename substitutions.

   Other substitutions (+)
       There   are  several  more  transformations  involving  filenames,  not
       strictly related to the above but mentioned here for completeness.  Any
       filename  may  be  expanded  to  a full path when the symlinks variable
       (q.v.) is set to `expand'.  Quoting prevents this  expansion,  and  the
       normalize-path editor command does it on demand.  The normalize-command
       editor command expands commands in PATH  into  full  paths  on  demand.
       Finally,  cd  and  pushd  interpret  `-'  as  the old working directory
       (equivalent to the shell variable owd).  This is not a substitution  at
       all,  but  an abbreviation recognized by only those commands.  Nonethe-
       less, it too can be prevented by quoting.

       The next three sections describe how the shell  executes  commands  and
       deals with their input and output.

   Simple commands, pipelines and sequences
       A  simple  command is a sequence of words, the first of which specifies
       the command to be executed.  A series of simple commands joined by  `|'
       characters  forms a pipeline.  The output of each command in a pipeline
       is connected to the input of the next.

       Simple commands and pipelines may be joined into  sequences  with  `;',
       and  will be executed sequentially.  Commands and pipelines can also be
       joined into sequences with `||' or `&&', indicating, as in the  C  lan-
       guage,  that  the  second  is to be executed only if the first fails or
       succeeds respectively.

       A simple command, pipeline or sequence may be  placed  in  parentheses,
       `()',  to  form a simple command, which may in turn be a component of a
       pipeline or sequence.  A command, pipeline or sequence can be  executed
       without waiting for it to terminate by following it with an `&'.

   Builtin and non-builtin command execution
       Builtin  commands are executed within the shell.  If any component of a
       pipeline except the last is a builtin command, the pipeline is executed
       in a subshell.

       Parenthesized commands are always executed in a subshell.

           (cd; pwd); pwd

       thus  prints  the  home directory, leaving you where you were (printing
       this after the home directory), while

           cd; pwd

       leaves you in the home  directory.   Parenthesized  commands  are  most
       often used to prevent cd from affecting the current shell.

       When  a command to be executed is found not to be a builtin command the
       shell attempts to execute the command via execve(2).  Each word in  the
       variable  path  names  a directory in which the shell will look for the
       command.  If the shell is not given a -f option, the shell  hashes  the
       names  in  these directories into an internal table so that it will try
       an execve(2) in only a directory where there is a possibility that  the
       command  resides  there.   This  greatly speeds command location when a
       large number of directories are present in the search path. This  hash-
       ing mechanism is not used:

       1.  If hashing is turned explicitly off via unhash.

       2.  If the shell was given a -f argument.

       3.  For  each  directory  component of path which does not begin with a

       4.  If the command contains a `/'.

       In the above four cases the shell concatenates each  component  of  the
       path  vector  with the given command name to form a path name of a file
       which it then attempts to execute it. If execution is  successful,  the
       search stops.

       If  the  file  has  execute permissions but is not an executable to the
       system (i.e., it is neither an executable  binary  nor  a  script  that
       specifies  its interpreter), then it is assumed to be a file containing
       shell commands and a new shell is spawned to read it.  The  shell  spe-
       cial  alias  may  be set to specify an interpreter other than the shell

       On systems which do not understand the `#!' script interpreter  conven-
       tion  the  shell  may  be compiled to emulate it; see the version shell
       variable.  If so, the shell checks the first line of the file to see if
       it  is of the form `#!interpreter arg ...'.  If it is, the shell starts
       interpreter with the given args and feeds the file to  it  on  standard

       The  standard  input and standard output of a command may be redirected
       with the following syntax:

       < name  Open file name (which is first variable, command  and  filename
               expanded) as the standard input.
       << word Read  the  shell input up to a line which is identical to word.
               word is not subjected to variable, filename or command  substi-
               tution, and each input line is compared to word before any sub-
               stitutions are done on this input line.  Unless a quoting  `\',
               `"',  `'  or ``' appears in word variable and command substitu-
               tion is performed on the intervening  lines,  allowing  `\'  to
               quote  `$',  `\'  and ``'.  Commands which are substituted have
               all blanks, tabs, and newlines preserved, except for the  final
               newline  which  is dropped.  The resultant text is placed in an
               anonymous temporary file which is given to the command as stan-
               dard input.
       > name
       >! name
       >& name
       >&! name
               The file name is used as standard output.  If the file does not
               exist then it is created; if the file exists, it is  truncated,
               its previous contents being lost.

               If  the shell variable noclobber is set, then the file must not
               exist or be a character  special  file  (e.g.,  a  terminal  or
               `/dev/null')  or an error results.  This helps prevent acciden-
               tal destruction of files.  In this case the `!'  forms  can  be
               used to suppress this check.

               The  forms  involving  `&' route the diagnostic output into the
               specified file  as  well  as  the  standard  output.   name  is
               expanded in the same way as `<' input filenames are.
       >> name
       >>& name
       >>! name
       >>&! name
               Like  `>', but appends output to the end of name.  If the shell
               variable noclobber is set, then it is an error for the file not
               to exist, unless one of the `!' forms is given.

       A  command  receives  the environment in which the shell was invoked as
       modified by the input-output parameters and the presence of the command
       in  a pipeline.  Thus, unlike some previous shells, commands run from a
       file of shell commands have no access to the text of  the  commands  by
       default;  rather they receive the original standard input of the shell.
       The `<<' mechanism should be used to present inline data.  This permits
       shell command scripts to function as components of pipelines and allows
       the shell to block read its input.   Note  that  the  default  standard
       input  for  a command run detached is not the empty file /dev/null, but
       the original standard input of the shell.  If this is a terminal and if
       the  process  attempts to read from the terminal, then the process will
       block and the user will be notified (see Jobs).

       Diagnostic output may be directed through a pipe with the standard out-
       put.  Simply use the form `|&' rather than just `|'.

       The  shell  cannot  presently  redirect  diagnostic output without also
       redirecting standard output, but `(command  >  output-file)  >&  error-
       file'  is often an acceptable workaround.  Either output-file or error-
       file may be `/dev/tty' to send output to the terminal.

       Having described how the shell accepts,  parses  and  executes  command
       lines, we now turn to a variety of its useful features.

   Control flow
       The  shell  contains a number of commands which can be used to regulate
       the flow of control in command files (shell scripts)  and  (in  limited
       but  useful  ways)  from terminal input.  These commands all operate by
       forcing the shell to reread or skip in its input and, due to the imple-
       mentation, restrict the placement of some of the commands.

       The  foreach, switch, and while statements, as well as the if-then-else
       form of the if statement, require that the major keywords appear  in  a
       single simple command on an input line as shown below.

       If  the shell's input is not seekable, the shell buffers up input when-
       ever a loop is being read and performs seeks in this internal buffer to
       accomplish the rereading implied by the loop.  (To the extent that this
       allows, backward gotos will succeed on non-seekable inputs.)

       The if, while and exit builtin commands use expressions with  a  common
       syntax.   The expressions can include any of the operators described in
       the next three sections.  Note that the @ builtin  command  (q.v.)  has
       its own separate syntax.

   Logical, arithmetical and comparison operators
       These operators are similar to those of C and have the same precedence.
       They include

           ||  &&  |  ^  &  ==  !=  =~  !~  <=  >=
           <  > <<  >>  +  -  *  /  %  !  ~  (  )

       Here the precedence increases to the right, `==' `!='  `=~'  and  `!~',
       `<='  `>='  `<'  and  `>',  `<<' and `>>', `+' and `-', `*' `/' and `%'
       being, in groups, at the same level.  The `==' `!=' `=~' and `!~' oper-
       ators  compare  their  arguments as strings; all others operate on num-
       bers.  The operators `=~' and `!~' are like `!=' and `=='  except  that
       the  right  hand  side  is  a  glob-pattern (see Filename substitution)
       against which the left hand operand is matched.  This reduces the  need
       for use of the switch builtin command in shell scripts when all that is
       really needed is pattern matching.

       Null or missing arguments are  considered  `0'.   The  results  of  all
       expressions are strings, which represent decimal numbers.  It is impor-
       tant to note that no two components of an expression can appear in  the
       same  word; except when adjacent to components of expressions which are
       syntactically significant to the parser (`&' `|' `<' `>' `(' `)')  they
       should be surrounded by spaces.

   Command exit status
       Commands  can be executed in expressions and their exit status returned
       by enclosing them in braces (`{}').  Remember that the braces should be
       separated  from the words of the command by spaces.  Command executions
       succeed, returning true, i.e., `1', if the command exits with status 0,
       otherwise they fail, returning false, i.e., `0'.  If more detailed sta-
       tus information is required then the command should be executed outside
       of an expression and the status shell variable examined.

   File inquiry operators
       Some  of  these operators perform true/false tests on files and related
       objects.  They are of the form -op file, where op is one of

           r   Read access
           w   Write access
           x   Execute access
           X   Executable in the path or shell builtin, e.g., `-X ls' and  `-X
               ls-F' are generally true, but `-X /bin/ls' is not (+)
           e   Existence
           o   Ownership
           z   Zero size
           s   Non-zero size (+)
           f   Plain file
           d   Directory
           l   Symbolic link (+) *
           b   Block special file (+)
           c   Character special file (+)
           p   Named pipe (fifo) (+) *
           S   Socket special file (+) *
           u   Set-user-ID bit is set (+)
           g   Set-group-ID bit is set (+)
           k   Sticky bit is set (+)
           t   file  (which  must be a digit) is an open file descriptor for a
               terminal device (+)
           R   Has been migrated (convex only) (+)
           L   Applies subsequent operators in a multiple-operator test  to  a
               symbolic  link rather than to the file to which the link points
               (+) *

       file is command and filename expanded and then tested to see if it  has
       the specified relationship to the real user.  If file does not exist or
       is inaccessible or, for the operators indicated by `*', if  the  speci-
       fied file type does not exist on the current system, then all enquiries
       return false, i.e., `0'.

       These operators may be combined for conciseness: `-xy file' is  equiva-
       lent  to `-x file && -y file'.  (+) For example, `-fx' is true (returns
       `1') for plain executable files, but not for directories.

       L may be used in a multiple-operator test to apply subsequent operators
       to  a  symbolic  link rather than to the file to which the link points.
       For example, `-lLo' is true for links owned by the invoking user.   Lr,
       Lw  and  Lx are always true for links and false for non-links.  L has a
       different meaning when it is the last operator in  a  multiple-operator
       test; see below.

       It  is  possible  but  not useful, and sometimes misleading, to combine
       operators which expect file to be a file with operators which  do  not,
       (e.g., X and t).  Following L with a non-file operator can lead to par-
       ticularly strange results.

       Other operators return other information, i.e., not just  `0'  or  `1'.
       (+) They have the same format as before; op may be one of

           A       Last  file  access time, as the number of seconds since the
           A:      Like A, but in timestamp format, e.g., `Fri May 14 16:36:10
           M       Last file modification time
           M:      Like M, but in timestamp format
           C       Last inode modification time
           C:      Like C, but in timestamp format
           D       Device number
           I       Inode number
           F       Composite file identifier, in the form device:inode
           L       The name of the file pointed to by a symbolic link
           N       Number of (hard) links
           P       Permissions, in octal, without leading zero
           P:      Like P, with leading zero
           Pmode   Equivalent  to  `-P file & mode', e.g., `-P22 file' returns
                   `22' if file is writable by group and  other,  `20'  if  by
                   group only, and `0' if by neither
           Pmode:  Like Pmode:, with leading zero
           U       Numeric userid
           U:      Username, or the numeric userid if the username is unknown
           G       Numeric groupid
           G:      Groupname,  or  the  numeric  groupid  if  the groupname is
           Z       Size, in bytes

       Only one of these operators may appear in a multiple-operator test, and
       it must be the last.  Note that L has a different meaning at the end of
       and elsewhere in a multiple-operator test.   Because  `0'  is  a  valid
       return  value  for many of these operators, they do not return `0' when
       they fail: most return `-1', and F returns `:'.

       If the shell is compiled with POSIX  defined  (see  the  version  shell
       variable), the result of a file inquiry is based on the permission bits
       of the file and not on the result of the access(2)  system  call.   For
       example, if one tests a file with -w whose permissions would ordinarily
       allow writing but which is on a file system mounted read-only, the test
       will succeed in a POSIX shell but fail in a non-POSIX shell.

       File  inquiry operators can also be evaluated with the filetest builtin
       command (q.v.) (+).

       The shell associates a job with each pipeline.  It  keeps  a  table  of
       current jobs, printed by the jobs command, and assigns them small inte-
       ger numbers.  When a job is started asynchronously with `&', the  shell
       prints a line which looks like

           [1] 1234

       indicating that the job which was started asynchronously was job number
       1 and had one (top-level) process, whose process id was 1234.

       If you are running a job and wish to do something else you may hit  the
       suspend  key  (usually  `^Z'), which sends a STOP signal to the current
       job.  The shell will then normally indicate that the job has been `Sus-
       pended'  and  print  another prompt.  If the listjobs shell variable is
       set, all jobs will be listed like the jobs builtin command;  if  it  is
       set  to `long' the listing will be in long format, like `jobs -l'.  You
       can then manipulate the state of the suspended job.  You can put it  in
       the  ``background''  with the bg command or run some other commands and
       eventually bring the job back into the ``foreground''  with  fg.   (See
       also  the  run-fg-editor  editor command.)  A `^Z' takes effect immedi-
       ately and is like an interrupt in that pending output and unread  input
       are  discarded  when  it is typed.  The wait builtin command causes the
       shell to wait for all background jobs to complete.

       The `^]' key sends a delayed suspend signal, which does not generate  a
       STOP signal until a program attempts to read(2) it, to the current job.
       This can usefully be typed ahead when you have prepared  some  commands
       for  a job which you wish to stop after it has read them.  The `^Y' key
       performs this function in csh(1); in tcsh, `^Y' is an editing  command.

       A  job  being  run in the background stops if it tries to read from the
       terminal.  Background jobs are normally allowed to produce output,  but
       this  can  be disabled by giving the command `stty tostop'.  If you set
       this tty option, then background jobs will stop when they try  to  pro-
       duce output like they do when they try to read input.

       There  are  several  ways to refer to jobs in the shell.  The character
       `%' introduces a job name.  If you wish to refer to job number  1,  you
       can  name  it  as `%1'.  Just naming a job brings it to the foreground;
       thus `%1' is a synonym for `fg %1', bringing job 1 back into the  fore-
       ground.  Similarly, saying `%1 &' resumes job 1 in the background, just
       like `bg %1'.  A job can also be named by an unambiguous prefix of  the
       string  typed  in to start it: `%ex' would normally restart a suspended
       ex(1) job, if there were only one suspended job whose name  began  with
       the  string  `ex'.   It is also possible to say `%?string' to specify a
       job whose text contains string, if there is only one such job.

       The shell maintains a notion of the current and previous jobs.  In out-
       put  pertaining  to  jobs, the current job is marked with a `+' and the
       previous job with a `-'.  The abbreviations `%+', `%', and (by  analogy
       with the syntax of the history mechanism) `%%' all refer to the current
       job, and `%-' refers to the previous job.

       The job control mechanism requires that the stty(1) option `new' be set
       on  some systems.  It is an artifact from a `new' implementation of the
       tty driver which allows generation of  interrupt  characters  from  the
       keyboard  to tell jobs to stop.  See stty(1) and the setty builtin com-
       mand for details on setting options in the new tty driver.

   Status reporting
       The shell learns immediately whenever a process changes state.  It nor-
       mally  informs  you  whenever  a job becomes blocked so that no further
       progress is possible, but only right before it prints a  prompt.   This
       is  done so that it does not otherwise disturb your work.  If, however,
       you set the shell variable notify, the shell will  notify  you  immedi-
       ately  of  changes of status in background jobs.  There is also a shell
       command notify which marks a single process so that its status  changes
       will  be  immediately  reported.   By  default notify marks the current
       process; simply say `notify' after starting a background  job  to  mark

       When  you  try  to  leave the shell while jobs are stopped, you will be
       warned that `You have stopped jobs.' You may use the  jobs  command  to
       see  what  they  are.  If you do this or immediately try to exit again,
       the shell will not warn you a second time, and the suspended jobs  will
       be terminated.

   Automatic, periodic and timed events (+)
       There are various ways to run commands and take other actions automati-
       cally at various times in the ``life cycle'' of the  shell.   They  are
       summarized  here, and described in detail under the appropriate Builtin
       commands, Special shell variables and Special aliases.

       The sched builtin command puts commands in a scheduled-event  list,  to
       be executed by the shell at a given time.

       The  beepcmd,  cwdcmd,  periodic,  precmd,  postcmd, and jobcmd Special
       aliases can be set, respectively, to execute commands  when  the  shell
       wants  to ring the bell, when the working directory changes, every tpe-
       riod minutes, before each prompt, before each  command  gets  executed,
       after  each  command  gets  executed,  and  when a job is started or is
       brought into the foreground.

       The autologout shell variable can be set to log out or lock  the  shell
       after a given number of minutes of inactivity.

       The  mail shell variable can be set to check for new mail periodically.

       The printexitvalue shell variable can be set to print the  exit  status
       of commands which exit with a status other than zero.

       The  rmstar  shell  variable can be set to ask the user, when `rm *' is
       typed, if that is really what was meant.

       The time shell variable can be set to execute the time builtin  command
       after the completion of any process that takes more than a given number
       of CPU seconds.

       The watch and who shell variables can be set to  report  when  selected
       users log in or out, and the log builtin command reports on those users
       at any time.

   Native Language System support (+)
       The shell is eight bit clean (if so compiled;  see  the  version  shell
       variable)  and  thus  supports  character sets needing this capability.
       NLS support differs depending on whether or not the shell was  compiled
       to  use  the  system's NLS (again, see version).  In either case, 7-bit
       ASCII is the default character code (e.g., the classification of  which
       characters  are  printable)  and  sorting,  and  changing  the  LANG or
       LC_CTYPE environment variables causes a check for possible  changes  in
       these respects.

       When  using  the  system's  NLS, the setlocale(3) function is called to
       determine appropriate character code/classification and sorting  (e.g.,
       a  'en_CA.UTF-8'  would yield "UTF-8" as a character code).  This func-
       tion typically examines the LANG and  LC_CTYPE  environment  variables;
       refer  to the system documentation for further details.  When not using
       the system's NLS, the shell simulates  it  by  assuming  that  the  ISO
       8859-1  character  set is used whenever either of the LANG and LC_CTYPE
       variables are set, regardless of their values.  Sorting is not affected
       for the simulated NLS.

       In addition, with both real and simulated NLS, all printable characters
       in the range \200-\377, i.e., those  that  have  M-char  bindings,  are
       automatically  rebound to self-insert-command.  The corresponding bind-
       ing for the escape-char sequence, if any, is left alone.  These charac-
       ters are not rebound if the NOREBIND environment variable is set.  This
       may be useful for the simulated NLS  or  a  primitive  real  NLS  which
       assumes  full  ISO 8859-1.  Otherwise, all M-char bindings in the range
       \240-\377 are effectively undone.  Explicitly  rebinding  the  relevant
       keys with bindkey is of course still possible.

       Unknown  characters (i.e., those that are neither printable nor control
       characters) are printed in the format \nnn.  If the tty is not in 8 bit
       mode,  other  8  bit characters are printed by converting them to ASCII
       and using standout mode.  The shell never changes the 7/8 bit  mode  of
       the  tty  and tracks user-initiated changes of 7/8 bit mode.  NLS users
       (or, for that matter, those who want to use a meta  key)  may  need  to
       explicitly  set  the  tty in 8 bit mode through the appropriate stty(1)
       command in, e.g., the ~/.login file.

   OS variant support (+)
       A number of new builtin commands are provided to  support  features  in
       particular  operating  systems.   All  are  described  in detail in the
       Builtin commands section.

       On  systems  that  support  TCF  (aix-ibm370,  aix-ps2),  getspath  and
       setspath  get  and set the system execution path, getxvers and setxvers
       get and set the experimental version prefix and migrate  migrates  pro-
       cesses  between  sites.  The jobs builtin prints the site on which each
       job is executing.

       Under BS2000, bs2cmd executes commands  of  the  underlying  BS2000/OSD
       operating system.

       Under  Domain/OS,  inlib  adds shared libraries to the current environ-
       ment, rootnode changes the rootnode and ver changes the systype.

       Under Mach, setpath is equivalent to Mach's setpath(1).

       Under Masscomp/RTU and Harris CX/UX, universe sets the universe.

       Under Harris CX/UX, ucb or att runs a command under the specified  uni-

       Under Convex/OS, warp prints or sets the universe.

       The  VENDOR, OSTYPE and MACHTYPE environment variables indicate respec-
       tively the vendor, operating system and  machine  type  (microprocessor
       class  or  machine model) of the system on which the shell thinks it is
       running.  These are particularly useful when sharing one's home  direc-
       tory between several types of machines; one can, for example,

           set path = (~/bin.$MACHTYPE /usr/ucb /bin /usr/bin .)

       in  one's ~/.login and put executables compiled for each machine in the
       appropriate directory.

       The version shell variable indicates what options were chosen when  the
       shell was compiled.

       Note  also  the  newgrp builtin, the afsuser and echo_style shell vari-
       ables and the system-dependent locations of  the  shell's  input  files
       (see FILES).

   Signal handling
       Login  shells  ignore  interrupts when reading the file ~/.logout.  The
       shell ignores quit signals unless started with -q.  Login shells  catch
       the terminate signal, but non-login shells inherit the terminate behav-
       ior from their parents.  Other signals have the values which the  shell
       inherited from its parent.

       In  shell scripts, the shell's handling of interrupt and terminate sig-
       nals can be controlled with onintr, and its handling of hangups can  be
       controlled with hup and nohup.

       The  shell  exits on a hangup (see also the logout shell variable).  By
       default, the shell's children do too, but the shell does not send  them
       a hangup when it exits.  hup arranges for the shell to send a hangup to
       a child when it exits, and nohup sets a child to ignore hangups.

   Terminal management (+)
       The shell uses  three  different  sets  of  terminal  (``tty'')  modes:
       `edit',  used  when editing, `quote', used when quoting literal charac-
       ters, and `execute', used when executing  commands.   The  shell  holds
       some settings in each mode constant, so commands which leave the tty in
       a confused state do not interfere  with  the  shell.   The  shell  also
       matches  changes  in the speed and padding of the tty.  The list of tty
       modes that are kept constant can be  examined  and  modified  with  the
       setty  builtin.  Note that although the editor uses CBREAK mode (or its
       equivalent), it takes typed-ahead characters anyway.

       The echotc, settc and telltc commands can be  used  to  manipulate  and
       debug terminal capabilities from the command line.

       On systems that support SIGWINCH or SIGWINDOW, the shell adapts to win-
       dow resizing automatically and adjusts the environment variables  LINES
       and  COLUMNS  if set.  If the environment variable TERMCAP contains li#
       and co# fields, the shell adjusts them to reflect the new window  size.


       The  next sections of this manual describe all of the available Builtin
       commands, Special aliases and Special shell variables.

   Builtin commands
       %job    A synonym for the fg builtin command.

       %job &  A synonym for the bg builtin command.

       :       Does nothing, successfully.

       @ name = expr
       @ name[index] = expr
       @ name++|--
       @ name[index]++|--
               The first form prints the values of all shell variables.

               The second form assigns the value of expr to name.   The  third
               form  assigns  the  value  of expr to the index'th component of
               name; both name and its index'th component must already  exist.

               expr  may  contain  the  operators `*', `+', etc., as in C.  If
               expr contains `<', `>', `&' or `' then at least  that  part  of
               expr  must be placed within `()'.  Note that the syntax of expr
               has nothing to do with that described under Expressions.

               The fourth and fifth forms increment (`++') or decrement (`--')
               name or its index'th component.

               The space between `@' and name is required.  The spaces between
               name and `=' and between `=' and expr are optional.  Components
               of expr must be separated by spaces.

       alias [name [wordlist]]
               Without  arguments,  prints all aliases.  With name, prints the
               alias for name.  With name and wordlist,  assigns  wordlist  as
               the  alias  of  name.  wordlist is command and filename substi-
               tuted.  name may not be `alias' or  `unalias'.   See  also  the
               unalias builtin command.

       alloc   Shows  the  amount of dynamic memory acquired, broken down into
               used and free memory.  With an argument  shows  the  number  of
               free  and  used  blocks  in each size category.  The categories
               start at size 8 and double at each step.  This command's output
               may  vary  across  system types, because systems other than the
               VAX may use a different memory allocator.

       bg [%job ...]
               Puts the specified jobs (or,  without  arguments,  the  current
               job)  into  the  background,  continuing each if it is stopped.
               job may be a number, a string, `', `%', `+' or `-' as described
               under Jobs.

       bindkey [-l|-d|-e|-v|-u] (+)
       bindkey [-a] [-b] [-k] [-r] [--] key (+)
       bindkey [-a] [-b] [-k] [-c|-s] [--] key command (+)
               Without  options,  the  first form lists all bound keys and the
               editor command to which each is bound, the  second  form  lists
               the  editor  command  to  which key is bound and the third form
               binds the editor command command to key.  Options include:

               -l  Lists all editor commands and a short description of  each.
               -d  Binds  all  keys  to  the standard bindings for the default
               -e  Binds all keys to the standard GNU Emacs-like bindings.
               -v  Binds all keys to the standard vi(1)-like bindings.
               -a  Lists or changes key-bindings in the alternative  key  map.
                   This is the key map used in vi command mode.
               -b  key  is interpreted as a control character written ^charac-
                   ter (e.g., `^A') or C-character (e.g., `C-A'), a meta char-
                   acter  written  M-character  (e.g.,  `M-A'), a function key
                   written F-string (e.g., `F-string'), or an extended  prefix
                   key written X-character (e.g., `X-A').
               -k  key  is interpreted as a symbolic arrow key name, which may
                   be one of `down', `up', `left' or `right'.
               -r  Removes key's binding.  Be careful: `bindkey -r'  does  not
                   bind key to self-insert-command (q.v.), it unbinds key com-
               -c  command is interpreted as a  builtin  or  external  command
                   instead of an editor command.
               -s  command  is taken as a literal string and treated as termi-
                   nal input when key is typed.  Bound  keys  in  command  are
                   themselves reinterpreted, and this continues for ten levels
                   of interpretation.
               --  Forces a break from option processing, so the next word  is
                   taken as key even if it begins with '-'.
               -u (or any invalid option)
                   Prints a usage message.

               key  may  be  a  single character or a string.  If a command is
               bound to a string, the first character of the string  is  bound
               to  sequence-lead-in and the entire string is bound to the com-

               Control characters in key can be literal (they can be typed  by
               preceding  them with the editor command quoted-insert, normally
               bound to `^V') or written caret-character  style,  e.g.,  `^A'.
               Delete is written `^?'  (caret-question mark).  key and command
               can contain backslashed escape sequences (in the style of  Sys-
               tem V echo(1)) as follows:

                   \a      Bell
                   \b      Backspace
                   \e      Escape
                   \f      Form feed
                   \n      Newline
                   \r      Carriage return
                   \t      Horizontal tab
                   \v      Vertical tab
                   \nnn    The ASCII character corresponding to the octal num-
                           ber nnn

               `\' nullifies the special meaning of the  following  character,
               if it has any, notably `\' and `^'.

       bs2cmd bs2000-command (+)
               Passes  bs2000-command  to  the  BS2000 command interpreter for
               execution. Only non-interactive commands can be  executed,  and
               it  is  not  possible to execute any command that would overlay
               the image of the current process, like /EXECUTE or /CALL-PROCE-
               DURE. (BS2000 only)

       break   Causes execution to resume after the end of the nearest enclos-
               ing foreach or while.  The remaining commands  on  the  current
               line  are  executed.   Multi-level  breaks are thus possible by
               writing them all on one line.

       breaksw Causes a break from a switch, resuming after the endsw.

       builtins (+)
               Prints the names of all builtin commands.

       bye (+) A synonym for the logout builtin command.   Available  only  if
               the shell was so compiled; see the version shell variable.

       case label:
               A label in a switch statement as discussed below.

       cd [-p] [-l] [-n|-v] [name]
               If  a  directory  name  is  given,  changes the shell's working
               directory to name.  If not, changes to home.  If name is `-' it
               is  interpreted  as  the  previous working directory (see Other
               substitutions).  (+) If name is not a subdirectory of the  cur-
               rent  directory  (and  does not begin with `/', `./' or `../'),
               each component of the variable cdpath is checked to see  if  it
               has  a  subdirectory name.  Finally, if all else fails but name
               is a shell variable whose value begins with `/', then  this  is
               tried to see if it is a directory.

               With -p, prints the final directory stack, just like dirs.  The
               -l, -n and -v flags have the same effect on cd as on dirs,  and
               they imply -p.  (+)

               See also the implicitcd shell variable.

       chdir   A synonym for the cd builtin command.

       complete [command [word/pattern/list[:select]/[[suffix]/] ...]] (+)
               Without  arguments, lists all completions.  With command, lists
               completions for command.  With command and word  etc.,  defines

               command may be a full command name or a glob-pattern (see File-
               name substitution).  It can begin with  `-'  to  indicate  that
               completion should be used only when command is ambiguous.

               word specifies which word relative to the current word is to be
               completed, and may be one of the following:

                   c   Current-word completion.   pattern  is  a  glob-pattern
                       which  must  match the beginning of the current word on
                       the command line.  pattern is ignored  when  completing
                       the current word.
                   C   Like  c,  but includes pattern when completing the cur-
                       rent word.
                   n   Next-word completion.  pattern is a glob-pattern  which
                       must  match  the  beginning of the previous word on the
                       command line.
                   N   Like n, but must match the beginning of  the  word  two
                       before the current word.
                   p   Position-dependent  completion.   pattern  is a numeric
                       range, with the same syntax used to index  shell  vari-
                       ables, which must include the current word.

               list,  the list of possible completions, may be one of the fol-

                   a       Aliases
                   b       Bindings (editor commands)
                   c       Commands (builtin or external commands)
                   C       External commands which  begin  with  the  supplied
                           path prefix
                   d       Directories
                   D       Directories which begin with the supplied path pre-
                   e       Environment variables
                   f       Filenames
                   F       Filenames which begin with the supplied path prefix
                   g       Groupnames
                   j       Jobs
                   l       Limits
                   n       Nothing
                   s       Shell variables
                   S       Signals
                   t       Plain (``text'') files
                   T       Plain  (``text'')  files  which begin with the sup-
                           plied path prefix
                   v       Any variables
                   u       Usernames
                   x       Like n, but  prints  select  when  list-choices  is
                   X       Completions
                   $var    Words from the variable var
                   (...)   Words from the given list
                   `...`   Words from the output of command

               select  is an optional glob-pattern.  If given, words from only
               list that match select are considered  and  the  fignore  shell
               variable  is  ignored.   The last three types of completion may
               not have a select pattern, and x uses select as an  explanatory
               message when the list-choices editor command is used.

               suffix  is  a  single  character to be appended to a successful
               completion.  If null, no character is appended.  If omitted (in
               which  case  the fourth delimiter can also be omitted), a slash
               is appended to directories and a space to other words.

               Now for some examples.  Some commands take only directories  as
               arguments, so there's no point completing plain files.

                   > complete cd 'p/1/d/'

               completes  only  the  first  word following `cd' (`p/1') with a
               directory.  p-type completion can also be used to  narrow  down
               command completion:

                   > co[^D]
                   complete compress
                   > complete -co* 'p/0/(compress)/'
                   > co[^D]
                   > compress

               This completion completes commands (words in position 0, `p/0')
               which begin with `co' (thus matching `co*') to `compress'  (the
               only  word  in  the list).  The leading `-' indicates that this
               completion is to be used with only ambiguous commands.

                   > complete find 'n/-user/u/'

               is an example of n-type completion.  Any word following  `find'
               and immediately following `-user' is completed from the list of

                   > complete cc 'c/-I/d/'

               demonstrates c-type completion.  Any word  following  `cc'  and
               beginning  with  `-I' is completed as a directory.  `-I' is not
               taken as part of the directory because we used lowercase c.

               Different lists are useful with different commands.

                   > complete alias 'p/1/a/'
                   > complete man 'p/*/c/'
                   > complete set 'p/1/s/'
                   > complete true 'p/1/x:Truth has no options./'

               These complete words following `alias' with aliases, `man' with
               commands,  and `set' with shell variables.  `true' doesn't have
               any options, so x does nothing when completion is attempted and
               prints  `Truth  has  no  options.'  when completion choices are

               Note that the man example, and several  other  examples  below,
               could just as well have used 'c/*' or 'n/*' as 'p/*'.

               Words  can be completed from a variable evaluated at completion

                   > complete ftp 'p/1/$hostnames/'
                   > set hostnames = (
                   > ftp [^D]
                   > ftp [^C]
                   >  set  hostnames  =   (
                   > ftp [^D]

               or from a command run at completion time:

                   > complete kill 'p/*/`ps | awk \{print\ \$1\}`/'
                   > kill -9 [^D]
                   23113 23377 23380 23406 23429 23529 23530 PID

               Note  that the complete command does not itself quote its argu-
               ments, so the braces, space and `$' in  `{print  $1}'  must  be
               quoted explicitly.

               One command can have multiple completions:

                   > complete dbx 'p/2/(core)/' 'p/*/c/'

               completes the second argument to `dbx' with the word `core' and
               all other arguments with commands.  Note  that  the  positional
               completion   is  specified  before  the  next-word  completion.
               Because completions are evaluated from left to  right,  if  the
               next-word completion were specified first it would always match
               and the positional completion would never be executed.  This is
               a common mistake when defining a completion.

               The  select  pattern  is useful when a command takes files with
               only particular forms as arguments.  For example,

                   > complete cc 'p/*/f:*.[cao]/'

               completes `cc' arguments to files ending in only `.c', `.a', or
               `.o'.  select can also exclude files, using negation of a glob-
               pattern as described under Filename  substitution.   One  might

                   > complete rm 'p/*/f:^*.{c,h,cc,C,tex,1,man,l,y}/'

               to  exclude  precious  source  code  from  `rm' completion.  Of
               course, one could still type excluded names manually  or  over-
               ride  the  completion  mechanism using the complete-word-raw or
               list-choices-raw editor commands (q.v.).

               The `C', `D', `F' and `T' lists are like `c', `d', `f' and  `t'
               respectively,  but  they use the select argument in a different
               way: to restrict completion to files beginning with a  particu-
               lar path prefix.  For example, the Elm mail program uses `=' as
               an abbreviation for one's mail directory.  One might use

                   > complete elm c@=@F:$HOME/Mail/@

               to complete `elm -f =' as if it were `elm  -f  ~/Mail/'.   Note
               that  we  used  `@'  instead of `/' to avoid confusion with the
               select argument, and we used `$HOME'  instead  of  `~'  because
               home  directory  substitution  works at only the beginning of a

               suffix is used to add a nonstandard suffix (not  space  or  `/'
               for directories) to completed words.

                   > complete finger 'c/*@/$hostnames/' 'p/1/u/@'

               completes arguments to `finger' from the list of users, appends
               an `@', and then completes after the `@' from  the  `hostnames'
               variable.   Note  again  the order in which the completions are

               Finally, here's a complex example for inspiration:

                   > complete find \
                   'n/-name/f/' 'n/-newer/f/' 'n/-{,n}cpio/f/' \
                   'n/-exec/c/' 'n/-ok/c/' 'n/-user/u/' \
                   'n/-group/g/' 'n/-fstype/(nfs 4.2)/' \
                   'n/-type/(b c d f l p s)/' \
                   'c/-/(name newer cpio ncpio exec ok user \
                   group fstype type atime ctime depth inum \
                   ls mtime nogroup nouser perm print prune \
                   size xdev)/' \

               This completes words following `-name',  `-newer',  `-cpio'  or
               `ncpio'  (note  the pattern which matches both) to files, words
               following `-exec' or `-ok' to commands, words following  `user'
               and  `group' to users and groups respectively and words follow-
               ing `-fstype' or `-type' to members of  the  given  lists.   It
               also  completes  the  switches  themselves  from the given list
               (note the use of c-type completion) and completes anything  not
               otherwise completed to a directory.  Whew.

               Remember  that  programmed  completions are ignored if the word
               being completed is a tilde substitution (beginning with `~') or
               a  variable  (beginning with `$').  complete is an experimental
               feature, and the syntax may change in future  versions  of  the
               shell.  See also the uncomplete builtin command.

               Continues  execution of the nearest enclosing while or foreach.
               The rest of the commands on the current line are executed.

               Labels the default case in a switch statement.  It should  come
               after all case labels.

       dirs [-l] [-n|-v]
       dirs -S|-L [filename] (+)
       dirs -c (+)
               The  first  form  prints  the  directory stack.  The top of the
               stack is at the left and the first directory in  the  stack  is
               the  current  directory.  With -l, `~' or `~name' in the output
               is expanded explicitly to home or  the  pathname  of  the  home
               directory  for  user  name.   (+)  With -n, entries are wrapped
               before they reach the edge of the screen.  (+) With -v, entries
               are  printed  one  per line, preceded by their stack positions.
               (+) If more than one of -n or -v is given, -v takes precedence.
               -p is accepted but does nothing.

               With  -S, the second form saves the directory stack to filename
               as a series of cd and  pushd  commands.   With  -L,  the  shell
               sources  filename,  which  is presumably a directory stack file
               saved by the -S option or the savedirs  mechanism.   In  either
               case,  dirsfile is used if filename is not given and ~/.cshdirs
               is used if dirsfile is unset.

               Note that login shells  do  the  equivalent  of  `dirs  -L'  on
               startup  and,  if  savedirs  is  set, `dirs -S' before exiting.
               Because only ~/.tcshrc is normally sourced  before  ~/.cshdirs,
               dirsfile should be set in ~/.tcshrc rather than ~/.login.

               The last form clears the directory stack.

       echo [-n] word ...
               Writes  each  word to the shell's standard output, separated by
               spaces and terminated with a  newline.   The  echo_style  shell
               variable  may  be  set to emulate (or not) the flags and escape
               sequences of the BSD and/or System  V  versions  of  echo;  see

       echotc [-sv] arg ... (+)
               Exercises  the  terminal capabilities (see termcap(5)) in args.
               For example, 'echotc home' sends the cursor to the  home  posi-
               tion,  'echotc  cm  3  10' sends it to column 3 and row 10, and
               'echotc ts 0; echo "This is a test."; echotc fs'  prints  "This
               is a test."  in the status line.

               If arg is 'baud', 'cols', 'lines', 'meta' or 'tabs', prints the
               value of that capability ("yes" or  "no"  indicating  that  the
               terminal does or does not have that capability).  One might use
               this to make the output from a shell  script  less  verbose  on
               slow  terminals, or limit command output to the number of lines
               on the screen:

                   > set history=`echotc lines`
                   > @ history--

               Termcap strings may contain wildcards which will not echo  cor-
               rectly.   One  should  use  double  quotes when setting a shell
               variable to a terminal capability string, as in  the  following
               example that places the date in the status line:

                   > set tosl="`echotc ts 0`"
                   > set frsl="`echotc fs`"
                   > echo -n "$tosl";date; echo -n "$frsl"

               With  -s,  nonexistent  capabilities  return  the  empty string
               rather than causing an error.  With -v, messages are verbose.

       endsw   See the description of  the  foreach,  if,  switch,  and  while
               statements below.

       eval arg ...
               Treats  the  arguments  as  input to the shell and executes the
               resulting command(s) in the context of the current shell.  This
               is  usually used to execute commands generated as the result of
               command or variable substitution, because parsing occurs before
               these substitutions.  See tset(1) for a sample use of eval.

       exec command
               Executes the specified command in place of the current shell.

       exit [expr]
               The shell exits either with the value of the specified expr (an
               expression, as described under Expressions) or,  without  expr,
               with the value 0.

       fg [%job ...]
               Brings  the  specified jobs (or, without arguments, the current
               job) into the foreground, continuing each  if  it  is  stopped.
               job may be a number, a string, `', `%', `+' or `-' as described
               under Jobs.  See also the run-fg-editor editor command.

       filetest -op file ... (+)
               Applies op (which is a file inquiry operator as described under
               File inquiry operators) to each file and returns the results as
               a space-separated list.

       foreach name (wordlist)
       end     Successively sets the variable name to each member of  wordlist
               and  executes the sequence of commands between this command and
               the matching end.  (Both foreach and end must appear  alone  on
               separate  lines.)   The builtin command continue may be used to
               continue the loop prematurely and the builtin command break  to
               terminate  it  prematurely.  When this command is read from the
               terminal, the loop is read once prompting with `foreach? '  (or
               prompt2)  before  any  statements in the loop are executed.  If
               you make a mistake typing in a loop at the terminal you can rub
               it out.

       getspath (+)
               Prints the system execution path.  (TCF only)

       getxvers (+)
               Prints the experimental version prefix.  (TCF only)

       glob wordlist
               Like  echo,  but the `-n' parameter is not recognized and words
               are delimited by null characters in  the  output.   Useful  for
               programs  which wish to use the shell to filename expand a list
               of words.

       goto word
               word is filename and command-substituted to yield a  string  of
               the  form `label'.  The shell rewinds its input as much as pos-
               sible, searches for a line of the form `label:', possibly  pre-
               ceded  by  blanks  or  tabs, and continues execution after that

               Prints a statistics line indicating how effective the  internal
               hash table has been at locating commands (and avoiding exec's).
               An exec is attempted for each component of the path  where  the
               hash  function  indicates a possible hit, and in each component
               which does not begin with a `/'.

               On machines without vfork(2), prints only the number  and  size
               of hash buckets.

       history [-hTr] [n]
       history -S|-L|-M [filename] (+)
       history -c (+)
               The  first  form  prints the history event list.  If n is given
               only the n most recent events are printed or saved.   With  -h,
               the  history list is printed without leading numbers.  If -T is
               specified, timestamps are printed also in comment form.   (This
               can be used to produce files suitable for loading with 'history
               -L' or 'source -h'.)  With -r, the order of  printing  is  most
               recent first rather than oldest first.

               With  -S,  the  second form saves the history list to filename.
               If the first word of the savehist shell variable is  set  to  a
               number,  at most that many lines are saved.  If the second word
               of savehist is set to `merge', the history list is merged  with
               the  existing history file instead of replacing it (if there is
               one) and sorted by time stamp.  (+) Merging is intended for  an
               environment  like  the  X  Window System with several shells in
               simultaneous use.  Currently it succeeds only when  the  shells
               quit nicely one after another.

               With -L, the shell appends filename, which is presumably a his-
               tory list saved by the -S option or the savehist mechanism,  to
               the  history list.  -M is like -L, but the contents of filename
               are merged into the history list and sorted by  timestamp.   In
               either  case,  histfile  is  used  if filename is not given and
               ~/.history is used if  histfile  is  unset.   `history  -L'  is
               exactly  like  'source  -h'  except  that it does not require a

               Note that login shells do the equivalent  of  `history  -L'  on
               startup  and,  if savehist is set, `history -S' before exiting.
               Because only ~/.tcshrc is normally sourced  before  ~/.history,
               histfile should be set in ~/.tcshrc rather than ~/.login.

               If  histlit  is  set, the first and second forms print and save
               the literal (unexpanded) form of the history list.

               The last form clears the history list.

       hup [command] (+)
               With command, runs command such that it will exit on  a  hangup
               signal  and  arranges  for the shell to send it a hangup signal
               when the shell exits.  Note that commands  may  set  their  own
               response  to  hangups,  overriding  hup.   Without  an argument
               (allowed in only a shell script), causes the shell to exit on a
               hangup  for  the remainder of the script.  See also Signal han-
               dling and the nohup builtin command.

       if (expr) command
               If expr (an expression, as described under Expressions)  evalu-
               ates  true, then command is executed.  Variable substitution on
               command happens early, at the same time it does for the rest of
               the  if  command.   command  must  be  a simple command, not an
               alias, a pipeline, a command list or  a  parenthesized  command
               list,  but  it  may  have  arguments.  Input/output redirection
               occurs even if expr is false and command is thus not  executed;
               this is a bug.

       if (expr) then
       else if (expr2) then
       endif   If  the  specified  expr is true then the commands to the first
               else are executed; otherwise if expr2 is true then the commands
               to  the  second  else are executed, etc.  Any number of else-if
               pairs are possible; only one endif is needed.  The else part is
               likewise  optional.   (The  words else and endif must appear at
               the beginning of input lines; the if must appear alone  on  its
               input line or after an else.)

       inlib shared-library ... (+)
               Adds  each shared-library to the current environment.  There is
               no way to remove a shared library.  (Domain/OS only)

       jobs [-l]
               Lists the active jobs.  With -l, lists process IDs in  addition
               to  the normal information.  On TCF systems, prints the site on
               which each job is executing.

       kill [-s signal] %job|pid ...
       kill -l The first and second forms sends the specified signal  (or,  if
               none  is  given,  the TERM (terminate) signal) to the specified
               jobs or processes.  job may be a number, a string, `', `%', `+'
               or  `-'  as  described under Jobs.  Signals are either given by
               number or by name (as given in /usr/include/signal.h,  stripped
               of  the  prefix  `SIG').   There is no default job; saying just
               `kill' does not send a signal to the current job.  If the  sig-
               nal  being  sent  is TERM (terminate) or HUP (hangup), then the
               job or process is sent a CONT (continue) signal as  well.   The
               third form lists the signal names.

       limit [-h] [resource [maximum-use]]
               Limits  the consumption by the current process and each process
               it creates to not individually exceed maximum-use on the speci-
               fied  resource.   If  no maximum-use is given, then the current
               limit is printed; if no resource is given, then all limitations
               are  given.   If the -h flag is given, the hard limits are used
               instead of the current limits.  The hard limits impose a  ceil-
               ing  on  the values of the current limits.  Only the super-user
               may raise the hard limits, but a user may lower  or  raise  the
               current limits within the legal range.

               Controllable  resources  currently include (if supported by the

                      the maximum number of cpu-seconds to  be  used  by  each

                      the largest single file which can be created

                      the  maximum growth of the data+stack region via sbrk(2)
                      beyond the end of the program text

                      the maximum size  of  the  automatically-extended  stack

                      the size of the largest core dump that will be created

                      the maximum amount of physical memory a process may have
                      allocated to it at a given time

                      the maximum amount of memory a process may allocate  per
                      brk() system call

               descriptors or openfiles
                      the maximum number of open files for this process

                      the maximum number of threads for this process

                      the  maximum  size  which a process may lock into memory
                      using mlock(2)

                      the maximum number of simultaneous  processes  for  this
                      user id

               sbsize the maximum size of socket buffer usage for this user

               maximum-use  may be given as a (floating point or integer) num-
               ber followed by a scale factor.   For  all  limits  other  than
               cputime the default scale is `k' or `kilobytes' (1024 bytes); a
               scale factor of `m' or  `megabytes'  may  also  be  used.   For
               cputime the default scaling is `seconds', while `m' for minutes
               or `h' for hours, or a time of the form `mm:ss' giving  minutes
               and seconds may be used.

               For both resource names and scale factors, unambiguous prefixes
               of the names suffice.

       log (+) Prints the watch shell variable and reports on each user  indi-
               cated  in  watch who is logged in, regardless of when they last
               logged in.  See also watchlog.

       login   Terminates a login shell, replacing  it  with  an  instance  of
               /bin/login.  This  is one way to log off, included for compati-
               bility with sh(1).

       logout  Terminates a login shell.  Especially useful  if  ignoreeof  is

       ls-F [-switch ...] [file ...] (+)
               Lists  files like `ls -F', but much faster.  It identifies each
               type of special file in the listing with a special character:

               /   Directory
               *   Executable
               #   Block device
               %   Character device
               |   Named pipe (systems with named pipes only)
               =   Socket (systems with sockets only)
               @   Symbolic link (systems with symbolic links only)
               +   Hidden directory (AIX only)  or  context  dependent  (HP/UX
               :   Network special (HP/UX only)

               If  the  listlinks  shell  variable  is set, symbolic links are
               identified in more detail (on only systems that have  them,  of

               @   Symbolic link to a non-directory
               >   Symbolic link to a directory
               &   Symbolic link to nowhere

               listlinks  also  slows  down ls-F and causes partitions holding
               files pointed to by symbolic links to be mounted.

               If the listflags shell variable is set to `x', `a' or  `A',  or
               any combination thereof (e.g., `xA'), they are used as flags to
               ls-F, making it act like `ls -xF', `ls -Fa', `ls -FA' or a com-
               bination  (e.g.,  `ls -FxA').  On machines where `ls -C' is not
               the default, ls-F acts like `ls -CF', unless listflags contains
               an  `x',  in which case it acts like `ls -xF'.  ls-F passes its
               arguments to ls(1) if it is given any switches,  so  `alias  ls
               ls-F' generally does the right thing.

               The  ls-F builtin can list files using different colors depend-
               ing on the filetype or extension.  See the color tcsh  variable
               and the LS_COLORS environment variable.

       migrate [-site] pid|%jobid ... (+)
       migrate -site (+)
               The  first  form migrates the process or job to the site speci-
               fied or the default site determined by the  system  path.   The
               second  form  is  equivalent to `migrate -site $$': it migrates
               the current process to the specified site.  Migrating the shell
               itself  can  cause  unexpected behavior, because the shell does
               not like to lose its tty.  (TCF only)

       newgrp [-] group (+)
               Equivalent to `exec newgrp'; see newgrp(1).  Available only  if
               the shell was so compiled; see the version shell variable.

       nice [+number] [command]
               Sets the scheduling priority for the shell to number, or, with-
               out number, to 4.  With command, runs command at the  appropri-
               ate priority.  The greater the number, the less cpu the process
               gets.  The super-user may specify negative  priority  by  using
               `nice -number ...'.  Command is always executed in a sub-shell,
               and the restrictions placed on commands in simple if statements

       nohup [command]
               With command, runs command such that it will ignore hangup sig-
               nals.  Note  that  commands  may  set  their  own  response  to
               hangups,  overriding  nohup.   Without  an argument (allowed in
               only a shell script), causes the shell to  ignore  hangups  for
               the  remainder of the script.  See also Signal handling and the
               hup builtin command.

       notify [%job ...]
               Causes the shell to notify the  user  asynchronously  when  the
               status of any of the specified jobs (or, without %job, the cur-
               rent job) changes, instead of waiting until the next prompt  as
               is  usual.   job may be a number, a string, `', `%', `+' or `-'
               as described under Jobs.  See also the notify shell variable.

       onintr [-|label]
               Controls the action of the shell on interrupts.  Without  argu-
               ments,  restores the default action of the shell on interrupts,
               which is to terminate shell scripts or to return to the  termi-
               nal command input level.  With `-', causes all interrupts to be
               ignored.  With label, causes  the  shell  to  execute  a  `goto
               label'  when an interrupt is received or a child process termi-
               nates because it was interrupted.

               onintr is ignored if the shell is running detached and in  sys-
               tem  startup  files  (see FILES), where interrupts are disabled

       popd [-p] [-l] [-n|-v] [+n]
               Without arguments, pops the directory stack and returns to  the
               new top directory.  With a number `+n', discards the n'th entry
               in the stack.

               Finally, all forms of popd print  the  final  directory  stack,
               just  like  dirs.  The pushdsilent shell variable can be set to
               prevent this and the -p flag can be given to override  pushdsi-
               lent.   The -l, -n and -v flags have the same effect on popd as
               on dirs.  (+)

       printenv [name] (+)
               Prints the names and values of all  environment  variables  or,
               with name, the value of the environment variable name.

       pushd [-p] [-l] [-n|-v] [name|+n]
               Without arguments, exchanges the top two elements of the direc-
               tory stack.  If pushdtohome is  set,  pushd  without  arguments
               does  `pushd  ~',  like  cd.  (+) With name, pushes the current
               working directory onto the directory stack and changes to name.
               If name is `-' it is interpreted as the previous working direc-
               tory (see Filename substitution).  (+) If dunique is set, pushd
               removes  any instances of name from the stack before pushing it
               onto the stack.  (+) With a number `+n', rotates the  nth  ele-
               ment  of  the  directory stack around to be the top element and
               changes to  it.   If  dextract  is  set,  however,  `pushd  +n'
               extracts the nth directory, pushes it onto the top of the stack
               and changes to it.  (+)

               Finally, all forms of pushd print the  final  directory  stack,
               just  like  dirs.  The pushdsilent shell variable can be set to
               prevent this and the -p flag can be given to override  pushdsi-
               lent.  The -l, -n and -v flags have the same effect on pushd as
               on dirs.  (+)

       rehash  Causes the internal hash table of the contents of the  directo-
               ries  in the path variable to be recomputed.  This is needed if
               new commands are added to directories in  path  while  you  are
               logged  in.   This should be necessary only if you add commands
               to one of your own directories,  or  if  a  systems  programmer
               changes  the  contents  of one of the system directories.  Also
               flushes the cache of home directories built by tilde expansion.

       repeat count command
               The  specified  command,  which is subject to the same restric-
               tions as the command in the one line  if  statement  above,  is
               executed  count  times.   I/O  redirections occur exactly once,
               even if count is 0.

       rootnode //nodename (+)
               Changes the rootnode to //nodename, so that `/' will be  inter-
               preted as `//nodename'.  (Domain/OS only)

       sched (+)
       sched [+]hh:mm command (+)
       sched -n (+)
               The  first  form  prints  the  scheduled-event list.  The sched
               shell variable may be set to define the  format  in  which  the
               scheduled-event  list is printed.  The second form adds command
               to the scheduled-event list.  For example,

                   > sched 11:00 echo It\'s eleven o\'clock.

               causes the shell to echo `It's eleven o'clock.' at 11 AM.   The
               time may be in 12-hour AM/PM format

                   > sched 5pm set prompt='[%h] It\'s after 5; go home: >'

               or may be relative to the current time:

                   > sched +2:15 /usr/lib/uucp/uucico -r1 -sother

               A  relative  time  specification may not use AM/PM format.  The
               third form removes item n from the event list:

                   > sched
                        1  Wed Apr  4 15:42  /usr/lib/uucp/uucico -r1 -sother
                        2  Wed Apr  4 17:00  set prompt=[%h] It's after 5;  go
                   home: >
                   > sched -2
                   > sched
                        1  Wed Apr  4 15:42  /usr/lib/uucp/uucico -r1 -sother

               A  command  in the scheduled-event list is executed just before
               the first prompt is printed after the time when the command  is
               scheduled.  It is possible to miss the exact time when the com-
               mand is to be run, but an overdue command will execute  at  the
               next  prompt.   A  command  which  comes due while the shell is
               waiting for user input is executed immediately.  However,  nor-
               mal  operation of an already-running command will not be inter-
               rupted so that a scheduled-event list element may be run.

               This mechanism is similar to, but not the same  as,  the  at(1)
               command  on  some Unix systems.  Its major disadvantage is that
               it may not run a command at exactly the  specified  time.   Its
               major  advantage  is  that because sched runs directly from the
               shell, it has access to shell variables and  other  structures.
               This  provides  a mechanism for changing one's working environ-
               ment based on the time of day.

       set name ...
       set name=word ...
       set [-r] [-f|-l] name=(wordlist) ... (+)
       set name[index]=word ...
       set -r (+)
       set -r name ... (+)
       set -r name=word ... (+)
               The first form of the command prints the  value  of  all  shell
               variables.   Variables  which  contain  more than a single word
               print as a parenthesized word list.  The second form sets  name
               to  the  null  string.   The third form sets name to the single
               word.  The fourth form sets  name  to  the  list  of  words  in
               wordlist.   In  all  cases  the  value  is command and filename
               expanded.  If -r is specified, the value is set read-only.   If
               -f  or  -l  are  specified, set only unique words keeping their
               order.  -f prefers the first occurrence of a word, and  -l  the
               last.   The  fifth  form sets the index'th component of name to
               word; this component must already exist.  The sixth form  lists
               only  the names of all shell variables that are read-only.  The
               seventh form makes name read-only, whether  or  not  it  has  a
               value.   The  second  form  sets  name to the null string.  The
               eighth form is the same as the third form, but make name  read-
               only at the same time.

               These  arguments  can  be repeated to set and/or make read-only
               multiple variables in a single  set  command.   Note,  however,
               that  variable  expansion  happens for all arguments before any
               setting occurs.  Note also that `=' can  be  adjacent  to  both
               name  and word or separated from both by whitespace, but cannot
               be adjacent to only one or  the  other.   See  also  the  unset
               builtin command.

       setenv [name [value]]
               Without  arguments, prints the names and values of all environ-
               ment variables.  Given name, sets the environment variable name
               to value or, without value, to the null string.

       setpath path (+)
               Equivalent to setpath(1).  (Mach only)

       setspath LOCAL|site|cpu ... (+)
               Sets the system execution path.  (TCF only)

       settc cap value (+)
               Tells the shell to believe that the terminal capability cap (as
               defined in termcap(5)) has the value value.  No sanity checking
               is  done.   Concept terminal users may have to `settc xn no' to
               get proper wrapping at the rightmost column.

       setty [-d|-q|-x] [-a] [[+|-]mode] (+)
               Controls which tty modes (see Terminal  management)  the  shell
               does  not  allow to change.  -d, -q or -x tells setty to act on
               the `edit', `quote' or `execute' set of tty modes respectively;
               without -d, -q or -x, `execute' is used.

               Without  other  arguments,  setty lists the modes in the chosen
               set which are fixed on (`+mode') or off (`-mode').  The  avail-
               able  modes,  and thus the display, vary from system to system.
               With -a, lists all tty modes in the chosen set whether  or  not
               they  are  fixed.   With +mode, -mode or mode, fixes mode on or
               off or removes control from mode in the chosen set.  For  exam-
               ple, `setty +echok echoe' fixes `echok' mode on and allows com-
               mands to turn `echoe' mode on or off, both when  the  shell  is
               executing commands.

       setxvers [string] (+)
               Set the experimental version prefix to string, or removes it if
               string is omitted.  (TCF only)

       shift [variable]
               Without arguments, discards argv[1] and shifts the  members  of
               argv  to the left.  It is an error for argv not to be set or to
               have less than one word as value.  With variable, performs  the
               same function on variable.

       source [-h] name [args ...]
               The  shell reads and executes commands from name.  The commands
               are not placed on the history list.  If  any  args  are  given,
               they are placed in argv.  (+) source commands may be nested; if
               they are nested too deeply  the  shell  may  run  out  of  file
               descriptors.   An error in a source at any level terminates all
               nested source commands.  With -h, commands are  placed  on  the
               history list instead of being executed, much like `history -L'.

       stop %job|pid ...
               Stops the specified jobs or processes which  are  executing  in
               the background.  job may be a number, a string, `', `%', `+' or
               `-' as described under Jobs.  There is no default  job;  saying
               just `stop' does not stop the current job.

       suspend Causes  the shell to stop in its tracks, much as if it had been
               sent a stop signal with ^Z.  This is most often  used  to  stop
               shells started by su(1).

       switch (string)
       case str1:
       endsw   Each  case label is successively matched, against the specified
               string which is first command and filename expanded.  The  file
               metacharacters  `*',  `?'  and `[...]'  may be used in the case
               labels, which are variable expanded.  If  none  of  the  labels
               match  before  a  `default'  label is found, then the execution
               begins after the  default  label.   Each  case  label  and  the
               default label must appear at the beginning of a line.  The com-
               mand breaksw causes execution  to  continue  after  the  endsw.
               Otherwise  control  may  fall  through  case labels and default
               labels as in C.  If no label matches and there is  no  default,
               execution continues after the endsw.

       telltc (+)
               Lists the values of all terminal capabilities (see termcap(5)).

       termname [terminal type] (+)
               Tests if terminal type (or the current value of TERM if no ter-
               minal  type  is  given) has an entry in the hosts termcap(5) or
               terminfo(5) database. Prints the terminal type  to  stdout  and
               returns 0 if an entry is present otherwise returns 1.

       time [command]
               Executes command (which must be a simple command, not an alias,
               a pipeline, a command list or a parenthesized command list) and
               prints a time summary as described under the time variable.  If
               necessary, an extra shell is created to print the time  statis-
               tic when the command completes.  Without command, prints a time
               summary for the current shell and its children.

       umask [value]
               Sets the file creation mask to value, which is given in  octal.
               Common  values  for  the mask are 002, giving all access to the
               group and read and execute access to others,  and  022,  giving
               read  and  execute  access  to  the  group and others.  Without
               value, prints the current file creation mask.

       unalias pattern
               Removes all aliases whose names  match  pattern.   `unalias  *'
               thus removes all aliases.  It is not an error for nothing to be

       uncomplete pattern (+)
               Removes all completions whose names match pattern.  `uncomplete
               *'  thus removes all completions.  It is not an error for noth-
               ing to be uncompleted.

       unhash  Disables use of the internal hash table to  speed  location  of
               executed programs.

       universe universe (+)
               Sets the universe to universe.  (Masscomp/RTU only)

       unlimit [-h] [resource]
               Removes the limitation on resource or, if no resource is speci-
               fied, all resource limitations.   With  -h,  the  corresponding
               hard  limits  are  removed.   Only  the super-user may do this.
               Note that unlimit may not exit successful, since  most  systems
               do not allow descriptors to be unlimited.

       unset pattern
               Removes  all  variables  whose names match pattern, unless they
               are read-only.  `unset *' thus  removes  all  variables  unless
               they are read-only; this is a bad idea.  It is not an error for
               nothing to be unset.

       unsetenv pattern
               Removes all environment variables whose  names  match  pattern.
               `unsetenv  *' thus removes all environment variables; this is a
               bad idea.  It is not an error for nothing to be unsetenved.

       ver [systype [command]] (+)
               Without arguments, prints SYSTYPE.  With systype, sets  SYSTYPE
               to  systype.   With systype and command, executes command under
               systype.  systype may  be  `bsd4.3'  or  `sys5.3'.   (Domain/OS

       wait    The  shell  waits  for  all  background  jobs.  If the shell is
               interactive, an interrupt will disrupt the wait and  cause  the
               shell  to  print  the  names and job numbers of all outstanding

       warp universe (+)
               Sets the universe to universe.  (Convex/OS only)

       watchlog (+)
               An alternate name for the log builtin command  (q.v.).   Avail-
               able  only  if the shell was so compiled; see the version shell

       where command (+)
               Reports all known  instances  of  command,  including  aliases,
               builtins and executables in path.

       which command (+)
               Displays  the  command that will be executed by the shell after
               substitutions, path searching, etc.   The  builtin  command  is
               just  like  which(1), but it correctly reports tcsh aliases and
               builtins and is 10 to 100 times faster.  See  also  the  which-
               command editor command.

       while (expr)
       end     Executes  the  commands  between the while and the matching end
               while expr (an  expression,  as  described  under  Expressions)
               evaluates  non-zero.   while and end must appear alone on their
               input lines.  break and continue may be used  to  terminate  or
               continue the loop prematurely.  If the input is a terminal, the
               user is prompted the first time through the loop as with  fore-

   Special aliases (+)
       If  set,  each of these aliases executes automatically at the indicated
       time.  They are all initially undefined.

       beepcmd Runs when the shell wants to ring the terminal bell.

       cwdcmd  Runs after every change of working directory.  For example,  if
               the  user is working on an X window system using xterm(1) and a
               re-parenting window manager that supports title  bars  such  as
               twm(1) and does

                   > alias cwdcmd  'echo -n "^[]2;${HOST}:$cwd ^G"'

               then the shell will change the title of the running xterm(1) to
               be the name of the host, a colon, and the full current  working
               directory.  A fancier way to do that is

                   >          alias          cwdcmd          'echo          -n

               This will put the hostname and working directory on  the  title
               bar but only the hostname in the icon manager menu.

               Note  that  putting  a cd, pushd or popd in cwdcmd may cause an
               infinite loop.  It is the author's opinion that anyone doing so
               will get what they deserve.

       jobcmd  Runs  before  each  command  gets executed, or when the command
               changes state.  This is similar to postcmd,  but  it  does  not
               print builtins.

                   > alias jobcmd  'echo -n "^[]2\;\!#^G"'

               then  executing  vi  foo.c  will  put the command string in the
               xterm title bar.

               Invoked by the run-help editor command.  The command  name  for
               which  help is sought is passed as sole argument.  For example,
               if one does

                   > alias helpcommand '\!:1 --help'

               then the help display of the command itself  will  be  invoked,
               using  the  GNU help calling convention.  Currently there is no
               easy way to account for various calling conventions (e.g.,  the
               customary Unix `-h'), except by using a table of many commands.

               Runs every tperiod minutes.  This provides a  convenient  means
               for checking on common but infrequent changes such as new mail.
               For example, if one does

                   > set tperiod = 30
                   > alias periodic checknews

               then the checknews(1) program runs every 30 minutes.  If  peri-
               odic  is set but tperiod is unset or set to 0, periodic behaves
               like precmd.

       precmd  Runs just before each prompt is printed.  For example,  if  one

                   > alias precmd date

               then  date(1)  runs just before the shell prompts for each com-
               mand.  There are no limits on what precmd can be set to do, but
               discretion should be used.

       postcmd Runs before each command gets executed.

                   > alias postcmd  'echo -n "^[]2\;\!#^G"'

               then  executing  vi  foo.c  will  put the command string in the
               xterm title bar.

       shell   Specifies the interpreter for executable scripts which  do  not
               themselves  specify an interpreter.  The first word should be a
               full path name to the desired interpreter (e.g., `/bin/csh'  or

   Special shell variables
       The  variables  described  in  this section have special meaning to the

       The  shell  sets  addsuffix,  argv,  autologout,  csubstnonl,  command,
       echo_style,  edit,  gid,  group,  home,  loginsh,  oid,  path,  prompt,
       prompt2, prompt3, shell, shlvl, tcsh, term, tty, uid, user and  version
       at  startup;  they do not change thereafter unless changed by the user.
       The shell updates cwd, dirstack, owd and  status  when  necessary,  and
       sets logout on logout.

       The shell synchronizes group, home, path, shlvl, term and user with the
       environment variables of the same names: whenever the environment vari-
       able  changes  the  shell  changes  the corresponding shell variable to
       match (unless the shell variable is read-only) and  vice  versa.   Note
       that  although  cwd  and PWD have identical meanings, they are not syn-
       chronized in this manner, and that the  shell  automatically  intercon-
       verts the different formats of path and PATH.

       addsuffix (+)
               If  set, filename completion adds `/' to the end of directories
               and a space to the end of normal files when  they  are  matched
               exactly.  Set by default.

       afsuser (+)
               If set, autologout's autolock feature uses its value instead of
               the local username for kerberos authentication.

       ampm (+)
               If set, all times are shown in 12-hour AM/PM format.

       argv    The arguments to the shell.  Positional  parameters  are  taken
               from  argv,  i.e., `$1' is replaced by `$argv[1]', etc.  Set by
               default, but usually empty in interactive shells.

       autocorrect (+)
               If set, the spell-word editor command is invoked  automatically
               before each completion attempt.

       autoexpand (+)
               If  set, the expand-history editor command is invoked automati-
               cally before each completion attempt.

       autolist (+)
               If set, possibilities are listed after an ambiguous completion.
               If  set  to  `ambiguous', possibilities are listed only when no
               new characters are added by completion.

       autologout (+)
               The first word is the number of minutes  of  inactivity  before
               automatic  logout.   The  optional second word is the number of
               minutes of inactivity before automatic locking.  When the shell
               automatically logs out, it prints `auto-logout', sets the vari-
               able logout to `automatic' and exits.  When the shell automati-
               cally locks, the user is required to enter his password to con-
               tinue working.  Five incorrect  attempts  result  in  automatic
               logout.  Set to `60' (automatic logout after 60 minutes, and no
               locking) by default in login and superuser shells, but  not  if
               the shell thinks it is running under a window system (i.e., the
               DISPLAY environment variable is set), the tty is  a  pseudo-tty
               (pty)  or  the shell was not so compiled (see the version shell
               variable).  See also the afsuser and logout shell variables.

       backslash_quote (+)
               If set, backslashes (`\') always quote `\', `'', and `"'.  This
               may  make complex quoting tasks easier, but it can cause syntax
               errors in csh(1) scripts.

       catalog The file name  of  the  message  catalog.   If  set,  tcsh  use
               `tcsh.${catalog}'  as  a  message  catalog  instead  of default

       cdpath  A list of directories in which cd should search for subdirecto-
               ries if they aren't found in the current directory.

       color   If  set,  it  enables color display for the builtin ls-F and it
               passes --color=auto to ls.  Alternatively, it  can  be  set  to
               only ls-F or only ls to enable color to only one command.  Set-
               ting it to nothing is equivalent to setting it to (ls-F ls).

               If set, it enables color escape sequence for NLS message files.
               And display colorful NLS messages.

       command (+)
               If  set,  the command which was passed to the shell with the -c
               flag (q.v.).

       complete (+)
               If set to `enhance', completion 1) ignores case and 2)  consid-
               ers  periods,  hyphens and underscores (`.', `-' and `_') to be
               word separators and hyphens and underscores to  be  equivalent.
               If set to `igncase', the completion becomes case insensitive.

       continue (+)
               If  set  to  a  list  of  commands, the shell will continue the
               listed commands, instead of starting a new one.

       continue_args (+)
               Same as continue, but the shell will execute:

                   echo `pwd` $argv > ~/.<cmd>_pause; %<cmd>

       correct (+)
               If set to `cmd', commands are automatically spelling-corrected.
               If set to `complete', commands are automatically completed.  If
               set to `all', the entire command line is corrected.

       csubstnonl (+)
               If set, newlines and carriage returns in  command  substitution
               are replaced by spaces.  Set by default.

       cwd     The  full  pathname  of  the  current  directory.  See also the
               dirstack and owd shell variables.

       dextract (+)
               If set, `pushd +n' extracts the nth directory from  the  direc-
               tory stack rather than rotating it to the top.

       dirsfile (+)
               The  default location in which `dirs -S' and `dirs -L' look for
               a history file.  If unset, ~/.cshdirs is  used.   Because  only
               ~/.tcshrc  is  normally  sourced  before  ~/.cshdirs,  dirsfile
               should be set in ~/.tcshrc rather than ~/.login.

       dirstack (+)
               An array  of  all  the  directories  on  the  directory  stack.
               `$dirstack[1]' is the current working directory, `$dirstack[2]'
               the first directory on the stack, etc.  Note that  the  current
               working directory is `$dirstack[1]' but `=0' in directory stack
               substitutions, etc.  One can change the  stack  arbitrarily  by
               setting  dirstack,  but  the first element (the current working
               directory) is always correct.  See also the cwd and  owd  shell

       dspmbyte (+)
               Has an affect iff 'dspm' is listed as part of the version shell
               variable.  If set to `euc', it enables display and editing EUC-
               kanji(Japanese) code.  If set to `sjis', it enables display and
               editing Shift-JIS(Japanese) code.  If set to `big5', it enables
               display  and  editing Big5(Chinese) code.  If set to `utf8', it
               enables display and editing Utf8(Unicode) code.  If set to  the
               following  format,  it  enables display and editing of original
               multi-byte code format:

                   > set dspmbyte = 0000....(256 bytes)....0000

               The table requires just 256 bytes.  Each character of 256 char-
               acters  corresponds  (from  left  to  right) to the ASCII codes
               0x00, 0x01, ... 0xff.  Each character is set  to  number  0,1,2
               and 3.  Each number has the following meaning:
                 0 ... not used for multi-byte characters.
                 1 ... used for the first byte of a multi-byte character.
                 2 ... used for the second byte of a multi-byte character.
                 3  ...  used  for  both  the  first byte and second byte of a
               multi-byte character.

               If set to `001322', the first  character  (means  0x00  of  the
               ASCII code) and second character (means 0x01 of ASCII code) are
               set to `0'.  Then, it is not used  for  multi-byte  characters.
               The  3rd  character (0x02) is set to '1', indicating that it is
               used for the first byte of a  multi-byte  character.   The  4th
               character(0x03) is set '3'.  It is used for both the first byte
               and the second byte of a multi-byte character.  The 5th and 6th
               characters (0x04,0x05) are set to '2', indicating that they are
               used for the second byte of a multi-byte character.

               The GNU fileutils version of ls cannot display multi-byte file-
               names  without  the -N ( --literal ) option.   If you are using
               this version, set the second word of dspmbyte to "ls".  If not,
               for example, "ls-F -l" cannot display multi-byte filenames.

               This  variable  can only be used if KANJI and DSPMBYTE has been
               defined at compile time.

       dunique (+)
               If set, pushd removes any instances  of  name  from  the  stack
               before pushing it onto the stack.

       echo    If  set,  each command with its arguments is echoed just before
               it is executed.  For non-builtin commands all expansions  occur
               before echoing.  Builtin commands are echoed before command and
               filename substitution, because  these  substitutions  are  then
               done selectively.  Set by the -x command line option.

       echo_style (+)
               The style of the echo builtin.  May be set to

               bsd     Don't echo a newline if the first argument is `-n'.
               sysv    Recognize backslashed escape sequences in echo strings.
               both    Recognize both the `-n'  flag  and  backslashed  escape
                       sequences; the default.
               none    Recognize neither.

               Set by default to the local system default.  The BSD and System
               V options are described in the echo(1) man pages on the  appro-
               priate systems.

       edit (+)
               If  set,  the  command-line  editor is used.  Set by default in
               interactive shells.

       ellipsis (+)
               If set, the `%c'/`%.' and `%C' prompt sequences (see the prompt
               shell  variable)  indicate skipped directories with an ellipsis
               (`...')  instead of `/<skipped>'.

       fignore (+)
               Lists file name suffixes to be ignored by completion.

       filec   In tcsh, completion is always used and this variable is ignored
               by  default. If edit is unset, then the traditional csh comple-
               tion is used.  If set in csh, filename completion is used.

       gid (+) The user's real group ID.

       group (+)
               The user's group name.

               If set, the incremental search match (in i-search-back  and  i-
               search-fwd)  and the region between the mark and the cursor are
               highlighted in reverse video.

               Highlighting requires  more  frequent  terminal  writes,  which
               introduces  extra  overhead. If you care about terminal perfor-
               mance, you may want to leave this unset.

               A string value determining the characters used in History  sub-
               stitution  (q.v.).  The first character of its value is used as
               the history substitution character, replacing the default char-
               acter  `!'.   The  second  character  of its value replaces the
               character `^' in quick substitutions.

       histdup (+)
               Controls handling of duplicate entries in the history list.  If
               set to `all' only unique history events are entered in the his-
               tory list.  If set to `prev' and the last history event is  the
               same  as  the  current command, then the current command is not
               entered in the history.  If set to `erase' and the  same  event
               is  found  in  the history list, that old event gets erased and
               the current one gets inserted.  Note that the `prev' and  `all'
               options renumber history events so there are no gaps.

       histfile (+)
               The  default  location  in  which `history -S' and `history -L'
               look for a history file.  If unset, ~/.history is used.   hist-
               file  is  useful  when  sharing the same home directory between
               different machines, or when saving separate histories  on  dif-
               ferent  terminals.   Because only ~/.tcshrc is normally sourced
               before ~/.history, histfile should be set in  ~/.tcshrc  rather
               than ~/.login.

       histlit (+)
               If  set, builtin and editor commands and the savehist mechanism
               use the literal (unexpanded) form of lines in the history list.
               See also the toggle-literal-history editor command.

       history The  first word indicates the number of history events to save.
               The optional second word (+) indicates the format in which his-
               tory  is  printed;  if  not given, `%h\t%T\t%R\n' is used.  The
               format sequences are described below  under  prompt;  note  the
               variable meaning of `%R'.  Set to `100' by default.

       home    Initialized to the home directory of the invoker.  The filename
               expansion of `~' refers to this variable.

               If set to the empty string or `0' and the  input  device  is  a
               terminal,  the  end-of-file  command  (usually generated by the
               user by typing `^D' on an empty line) causes the shell to print
               `Use  "exit" to leave tcsh.' instead of exiting.  This prevents
               the shell from accidentally being  killed.   Historically  this
               setting  exited  after  26  successive  EOF's to avoid infinite
               loops.  If set to a number n, the shell ignores n - 1  consecu-
               tive  end-of-files  and exits on the nth.  (+) If unset, `1' is
               used, i.e., the shell exits on a single `^D'.

       implicitcd (+)
               If set, the shell treats a directory name typed as a command as
               though  it  were a request to change to that directory.  If set
               to verbose, the change of directory is echoed to  the  standard
               output.   This  behavior  is inhibited in non-interactive shell
               scripts, or for  command  strings  with  more  than  one  word.
               Changing directory takes precedence over executing a like-named
               command, but it is done after alias substitutions.   Tilde  and
               variable expansions work as expected.

       inputmode (+)
               If  set  to  `insert' or `overwrite', puts the editor into that
               input mode at the beginning of each line.

       killdup (+)
               Controls handling of duplicate entries in the  kill  ring.   If
               set  to `all' only unique strings are entered in the kill ring.
               If set to `prev' and the last killed string is the same as  the
               current  killed  string, then the current string is not entered
               in the ring.  If set to `erase' and the same string is found in
               the  kill ring, the old string is erased and the current one is

       killring (+)
               Indicates the number of killed strings to keep in memory.   Set
               to  `30'  by  default.   If  unset or set to less than `2', the
               shell will only keep the most recently killed string.   Strings
               are  put  in  the  killring  by the editor commands that delete
               (kill) strings of text, e.g.  backward-delete-word,  kill-line,
               etc, as well as the copy-region-as-kill command.  The yank edi-
               tor command will yank the most recently killed string into  the
               command-line,  while yank-pop (see Editor commands) can be used
               to yank earlier killed strings.

       listflags (+)
               If set to `x', `a' or `A', or any  combination  thereof  (e.g.,
               `xA'),  they  are used as flags to ls-F, making it act like `ls
               -xF', `ls -Fa', `ls -FA' or a combination  (e.g.,  `ls  -FxA'):
               `a'  shows all files (even if they start with a `.'), `A' shows
               all files but `.' and `..', and `x'  sorts  across  instead  of
               down.   If  the  second word of listflags is set, it is used as
               the path to `ls(1)'.

       listjobs (+)
               If set, all jobs are listed when a job is suspended.  If set to
               `long', the listing is in long format.

       listlinks (+)
               If  set,  the  ls-F  builtin  command shows the type of file to
               which each symbolic link points.

       listmax (+)
               The maximum number of items which the list-choices editor  com-
               mand will list without asking first.

       listmaxrows (+)
               The maximum number of rows of items which the list-choices edi-
               tor command will list without asking first.

       loginsh (+)
               Set by the shell if it is a login shell.  Setting or  unsetting
               it within a shell has no effect.  See also shlvl.

       logout (+)
               Set  by  the  shell  to `normal' before a normal logout, `auto-
               matic' before an automatic logout, and `hangup'  if  the  shell
               was  killed by a hangup signal (see Signal handling).  See also
               the autologout shell variable.

       mail    The names of the files or directories  to  check  for  incoming
               mail,  separated  by  whitespace,  and optionally preceded by a
               numeric word.  Before each prompt, if 10  minutes  have  passed
               since  the last check, the shell checks each file and says `You
               have new mail.' (or, if mail contains multiple files, `You have
               new  mail  in  name.')  if the filesize is greater than zero in
               size and has a modification time greater than its access  time.

               If  you  are  in  a  login shell, then no mail file is reported
               unless it has been  modified  after  the  time  the  shell  has
               started  up,  to  prevent  redundant notifications.  Most login
               programs will tell you whether or not you have  mail  when  you
               log in.

               If  a  file  specified  in  mail is a directory, the shell will
               count each file within that directory as  a  separate  message,
               and  will  report  `You  have n mails.' or `You have n mails in
               name.' as appropriate.  This functionality is provided  primar-
               ily  for those systems which store mail in this manner, such as
               the Andrew Mail System.

               If the first word of mail is numeric it is taken as a different
               mail checking interval, in seconds.

               Under  very  rare circumstances, the shell may report `You have
               mail.' instead of `You have new mail.'

       matchbeep (+)
               If  set  to  `never',  completion  never  beeps.   If  set   to
               `nomatch',  it  beeps  only  when there is no match.  If set to
               `ambiguous', it beeps when there are multiple matches.  If  set
               to  `notunique',  it  beeps  when  there is one exact and other
               longer matches.  If unset, `ambiguous' is used.

       nobeep (+)
               If set, beeping is completely disabled.  See also  visiblebell.

               If set, restrictions are placed on output redirection to insure
               that files are not accidentally destroyed and that  `>>'  redi-
               rections   refer   to  existing  files,  as  described  in  the
               Input/output section.

       noding  If set, disable the printing of  `DING!'  in  the  prompt  time
               specifiers at the change of hour.

       noglob  If  set, Filename substitution and Directory stack substitution
               (q.v.) are inhibited.  This is most  useful  in  shell  scripts
               which  do not deal with filenames, or after a list of filenames
               has been obtained and further expansions are not desirable.

       nokanji (+)
               If set and the shell supports  Kanji  (see  the  version  shell
               variable), it is disabled so that the meta key can be used.

               If set, a Filename substitution or Directory stack substitution
               (q.v.)  which  does  not  match  any  existing  files  is  left
               untouched  rather  than causing an error.  It is still an error
               for the substitution to be  malformed,  e.g.,  `echo  ['  still
               gives an error.

       nostat (+)
               A  list  of  directories (or glob-patterns which match directo-
               ries; see Filename substitution) that should not  be  stat(2)ed
               during a completion operation.  This is usually used to exclude
               directories which take too much time to  stat(2),  for  example

       notify  If  set,  the  shell  announces job completions asynchronously.
               The default is to present job completions just before  printing
               a prompt.

       oid (+) The user's real organization ID.  (Domain/OS only)

       owd (+) The old working directory, equivalent to the `-' used by cd and
               pushd.  See also the cwd and dirstack shell variables.

       padhour If set, enable the printing of padding '0' for hours, in 24 and
               12 hour formats.  E.G.: 07:45:42 vs. 7:45:42

       path    A list of directories in which to look for executable commands.
               A null word specifies the current directory.  If  there  is  no
               path  variable then only full path names will execute.  path is
               set by the shell at startup from the PATH environment  variable
               or, if PATH does not exist, to a system-dependent default some-
               thing like `(/usr/local/bin /usr/bsd /bin  /usr/bin  .)'.   The
               shell  may  put  `.'  first or last in path or omit it entirely
               depending on how it was compiled; see the version  shell  vari-
               able.   A shell which is given neither the -c nor the -t option
               hashes the contents of the directories in  path  after  reading
               ~/.tcshrc  and each time path is reset.  If one adds a new com-
               mand to a directory in path while the shell is active, one  may
               need to do a rehash for the shell to find it.

       printexitvalue (+)
               If set and an interactive program exits with a non-zero status,
               the shell prints `Exit status'.

       prompt  The string which is printed before reading  each  command  from
               the  terminal.  prompt may include any of the following format-
               ting sequences (+), which are replaced by  the  given  informa-

               %/  The current working directory.
               %~  The  current  working directory, but with one's home direc-
                   tory represented by `~' and other users'  home  directories
                   represented   by  `~user'  as  per  Filename  substitution.
                   `~user' substitution happens only if the shell has  already
                   used `~user' in a pathname in the current session.
               %c[[0]n], %.[[0]n]
                   The trailing component of the current working directory, or
                   n trailing components if a digit n is given.  If  n  begins
                   with  `0',  the  number  of  skipped components precede the
                   trailing component(s) in the  format  `/<skipped>trailing'.
                   If  the  ellipsis shell variable is set, skipped components
                   are  represented  by  an  ellipsis  so  the  whole  becomes
                   `...trailing'.   `~' substitution is done as in `%~' above,
                   but the `~' component is  ignored  when  counting  trailing
               %C  Like %c, but without `~' substitution.
               %h, %!, !
                   The current history event number.
               %M  The full hostname.
               %m  The hostname up to the first `.'.
               %S (%s)
                   Start (stop) standout mode.
               %B (%b)
                   Start (stop) boldfacing mode.
               %U (%u)
                   Start (stop) underline mode.
               %t, %@
                   The time of day in 12-hour AM/PM format.
               %T  Like  `%t',  but  in 24-hour format (but see the ampm shell
               %p  The `precise' time of day in  12-hour  AM/PM  format,  with
               %P  Like  `%p',  but  in 24-hour format (but see the ampm shell
               \c  c is parsed as in bindkey.
               ^c  c is parsed as in bindkey.
               %%  A single `%'.
               %n  The user name.
               %j  The number of jobs.
               %d  The weekday in `Day' format.
               %D  The day in `dd' format.
               %w  The month in `Mon' format.
               %W  The month in `mm' format.
               %y  The year in `yy' format.
               %Y  The year in `yyyy' format.
               %l  The shell's tty.
               %L  Clears from the end of the prompt to end of the display  or
                   the end of the line.
               %$  Expands  the shell or environment variable name immediately
                   after the `$'.
               %#  `>' (or the first character of the promptchars shell  vari-
                   able)  for  normal  users,  `#' (or the second character of
                   promptchars) for the superuser.
                   Includes string as a literal escape sequence.  It should be
                   used only to change terminal attributes and should not move
                   the cursor location.  This cannot be the last  sequence  in
               %?  The  return  code  of  the command executed just before the
               %R  In prompt2, the status of the parser.  In prompt3, the cor-
                   rected string.  In history, the history string.

               `%B',  `%S', `%U' and `%{string%}' are available in only eight-
               bit-clean shells; see the version shell variable.

               The bold, standout and underline sequences are  often  used  to
               distinguish a superuser shell.  For example,

                   > set prompt = "%m [%h] %B[%@]%b [%/] you rang? "
                   tut [37] [2:54pm] [/usr/accts/sys] you rang? _

               If  `%t',  `%@', `%T', `%p', or `%P' is used, and noding is not
               set, then print `DING!' on the change of hour (i.e, `:00'  min-
               utes) instead of the actual time.

               Set by default to `%# ' in interactive shells.

       prompt2 (+)
               The  string with which to prompt in while and foreach loops and
               after lines ending in `\'.  The same format  sequences  may  be
               used  as  in  prompt (q.v.); note the variable meaning of `%R'.
               Set by default to `%R? ' in interactive shells.

       prompt3 (+)
               The string with  which  to  prompt  when  confirming  automatic
               spelling  correction.  The same format sequences may be used as
               in prompt (q.v.); note the variable meaning of  `%R'.   Set  by
               default to `CORRECT>%R (y|n|e|a)? ' in interactive shells.

       promptchars (+)
               If  set  (to  a  two-character  string),  the  `%#'  formatting
               sequence in the prompt shell  variable  is  replaced  with  the
               first  character  for normal users and the second character for
               the superuser.

       pushdtohome (+)
               If set, pushd without arguments does `pushd ~', like cd.

       pushdsilent (+)
               If set, pushd and popd do not print the directory stack.

       recexact (+)
               If set, completion completes on an exact match even if a longer
               match is possible.

       recognize_only_executables (+)
               If  set,  command  listing displays only files in the path that
               are executable.  Slow.

       rmstar (+)
               If set, the user is prompted before `rm *' is executed.

       rprompt (+)
               The string to print on the right-hand side of the screen (after
               the  command  input)  when the prompt is being displayed on the
               left.  It recognizes the same formatting characters as  prompt.
               It  will  automatically disappear and reappear as necessary, to
               ensure that command input isn't obscured, and will appear  only
               if  the  prompt, command input, and itself will fit together on
               the first line.  If  edit  isn't  set,  then  rprompt  will  be
               printed after the prompt and before the command input.

       savedirs (+)
               If  set, the shell does `dirs -S' before exiting.  If the first
               word is set to a number, at  most  that  many  directory  stack
               entries are saved.

               If  set,  the  shell  does `history -S' before exiting.  If the
               first word is set to a number, at  most  that  many  lines  are
               saved.  (The number must be less than or equal to history.)  If
               the second word is set to `merge', the history list  is  merged
               with  the  existing  history  file  instead of replacing it (if
               there is one) and sorted by time  stamp  and  the  most  recent
               events are retained.  (+)

       sched (+)
               The  format in which the sched builtin command prints scheduled
               events; if not  given,  `%h\t%T\t%R\n'  is  used.   The  format
               sequences  are  described above under prompt; note the variable
               meaning of `%R'.

       shell   The file in which the shell resides.  This is used  in  forking
               shells  to  interpret  files  which  have execute bits set, but
               which are not executable by the system.  (See  the  description
               of  Builtin and non-builtin command execution.)  Initialized to
               the (system-dependent) home of the shell.

       shlvl (+)
               The number of nested shells.  Reset to 1 in login shells.   See
               also loginsh.

       status  The  status  returned  by  the  last command.  If it terminated
               abnormally, then 0200 is added to the status.  Builtin commands
               which  fail  return exit status `1', all other builtin commands
               return status `0'.

       symlinks (+)
               Can be set to several different values to control symbolic link
               (`symlink') resolution:

               If  set to `chase', whenever the current directory changes to a
               directory containing a symbolic link, it  is  expanded  to  the
               real name of the directory to which the link points.  This does
               not work for the user's home directory; this is a bug.

               If set to `ignore', the shell  tries  to  construct  a  current
               directory relative to the current directory before the link was
               crossed.  This means that cding through  a  symbolic  link  and
               then  `cd  ..'ing  returns one to the original directory.  This
               affects only builtin commands and filename completion.

               If set to `expand', the shell tries to fix  symbolic  links  by
               actually  expanding arguments which look like path names.  This
               affects any command, not just  builtins.   Unfortunately,  this
               does  not  work  for hard-to-recognize filenames, such as those
               embedded in command options.  Expansion  may  be  prevented  by
               quoting.  While this setting is usually the most convenient, it
               is sometimes misleading and sometimes confusing when  it  fails
               to  recognize  an argument which should be expanded.  A compro-
               mise is to use `ignore' and use the editor  command  normalize-
               path (bound by default to ^X-n) when necessary.

               Some  examples  are  in  order.   First, let's set up some play

                   > cd /tmp
                   > mkdir from from/src to
                   > ln -s from/src to/dst

               Here's the behavior with symlinks unset,

                   > cd /tmp/to/dst; echo $cwd
                   > cd ..; echo $cwd

               here's the behavior with symlinks set to `chase',

                   > cd /tmp/to/dst; echo $cwd
                   > cd ..; echo $cwd

               here's the behavior with symlinks set to `ignore',

                   > cd /tmp/to/dst; echo $cwd
                   > cd ..; echo $cwd

               and here's the behavior with symlinks set to `expand'.

                   > cd /tmp/to/dst; echo $cwd
                   > cd ..; echo $cwd
                   > cd /tmp/to/dst; echo $cwd
                   > cd ".."; echo $cwd
                   > /bin/echo ..
                   > /bin/echo ".."

               Note that `expand' expansion 1) works just  like  `ignore'  for
               builtins  like  cd,  2) is prevented by quoting, and 3) happens
               before filenames are passed to non-builtin commands.

       tcsh (+)
               The version number of the shell in the format `R.VV.PP',  where
               `R'  is  the major release number, `VV' the current version and
               `PP' the patchlevel.

       term    The terminal type.  Usually set in ~/.login as described  under
               Startup and shutdown.

       time    If set to a number, then the time builtin (q.v.) executes auto-
               matically after each command which takes more  than  that  many
               CPU seconds.  If there is a second word, it is used as a format
               string for the output of the time builtin.  (u)  The  following
               sequences may be used in the format string:

               %U  The time the process spent in user mode in cpu seconds.
               %S  The time the process spent in kernel mode in cpu seconds.
               %E  The elapsed (wall clock) time in seconds.
               %P  The CPU percentage computed as (%U + %S) / %E.
               %W  Number of times the process was swapped.
               %X  The average amount in (shared) text space used in Kbytes.
               %D  The  average  amount in (unshared) data/stack space used in
               %K  The total space used (%X + %D) in Kbytes.
               %M  The maximum memory the process had in use at  any  time  in
               %F  The  number of major page faults (page needed to be brought
                   from disk).
               %R  The number of minor page faults.
               %I  The number of input operations.
               %O  The number of output operations.
               %r  The number of socket messages received.
               %s  The number of socket messages sent.
               %k  The number of signals received.
               %w  The number of voluntary context switches (waits).
               %c  The number of involuntary context switches.

               Only the first four sequences are supported on systems  without
               BSD  resource limit functions.  The default time format is `%Uu
               %Ss %E %P %X+%Dk %I+%Oio %Fpf+%Ww'  for  systems  that  support
               resource  usage  reporting and `%Uu %Ss %E %P' for systems that
               do not.

               Under Sequent's DYNIX/ptx, %X, %D, %K, %r and %s are not avail-
               able, but the following additional sequences are:

               %Y  The number of system calls performed.
               %Z  The number of pages which are zero-filled on demand.
               %i  The  number  of  times  a  process's  resident set size was
                   increased by the kernel.
               %d  The number of times  a  process's  resident  set  size  was
                   decreased by the kernel.
               %l  The number of read system calls performed.
               %m  The number of write system calls performed.
               %p  The number of reads from raw disk devices.
               %q  The number of writes to raw disk devices.

               and  the  default  time  format  is  `%Uu  %Ss  %E  %P  %I+%Oio
               %Fpf+%Ww'.  Note that the CPU percentage  can  be  higher  than
               100% on multi-processors.

       tperiod (+)
               The period, in minutes, between executions of the periodic spe-
               cial alias.

       tty (+) The name of the tty, or empty if not attached to one.

       uid (+) The user's real user ID.

       user    The user's login name.

       verbose If set, causes the words of each command to be  printed,  after
               history  substitution  (if  any).   Set  by the -v command line

       version (+)
               The version ID stamp.  It contains the shell's  version  number
               (see  tcsh), origin, release date, vendor, operating system and
               machine (see VENDOR, OSTYPE and MACHTYPE) and a comma-separated
               list  of options which were set at compile time.  Options which
               are set by default in the distribution are noted.

               8b    The shell is eight bit clean; default
               7b    The shell is not eight bit clean
               wide  The shell is multibyte encoding clean (like UTF-8)
               nls   The system's NLS is used; default for systems with NLS
               lf    Login shells execute  /etc/csh.login  before  instead  of
                     after /etc/csh.cshrc and ~/.login before instead of after
                     ~/.tcshrc and ~/.history.
               dl    `.' is put last in path for security; default
               nd    `.' is omitted from path for security
               vi    vi-style editing is the default rather than emacs
               dtr   Login shells drop DTR when exiting
               bye   bye is a synonym for logout and log is an alternate  name
                     for watchlog
               al    autologout is enabled; default
               kan   Kanji  is  used  if  appropriate according to locale set-
                     tings, unless the nokanji shell variable is set
               sm    The system's malloc(3) is used
               hb    The `#!<program> <args>' convention is emulated when exe-
                     cuting shell scripts
               ng    The newgrp builtin is available
               rh    The  shell  attempts  to  set  the REMOTEHOST environment
               afs   The shell verifies your password with the kerberos server
                     if  local  authentication fails.  The afsuser shell vari-
                     able or the AFSUSER environment  variable  override  your
                     local username if set.

               An  administrator may enter additional strings to indicate dif-
               ferences in the local version.

       visiblebell (+)
               If set, a screen flash is used rather than  the  audible  bell.
               See also nobeep.

       watch (+)
               A  list of user/terminal pairs to watch for logins and logouts.
               If either the user is `any' all terminals are watched  for  the
               given  user  and  vice  versa.   Setting  watch  to `(any any)'
               watches all users and terminals.  For example,

                   set watch = (george ttyd1 any console $user any)

               reports activity of the user `george' on ttyd1, any user on the
               console, and oneself (or a trespasser) on any terminal.

               Logins and logouts are checked every 10 minutes by default, but
               the first word of watch can be set to a number to  check  every
               so many minutes.  For example,

                   set watch = (1 any any)

               reports any login/logout once every minute.  For the impatient,
               the log builtin command triggers a watch report  at  any  time.
               All  current logins are reported (as with the log builtin) when
               watch is first set.

               The who shell variable controls the format of watch reports.

       who (+) The format string for watch messages.  The following  sequences
               are replaced by the given information:

               %n  The name of the user who logged in/out.
               %a  The  observed  action,  i.e.,  `logged on', `logged off' or
                   `replaced olduser on'.
               %l  The terminal (tty) on which the user logged in/out.
               %M  The full hostname of the remote host,  or  `local'  if  the
                   login/logout was from the local host.
               %m  The  hostname  of the remote host up to the first `.'.  The
                   full name is printed if it is an IP address or an X  Window
                   System display.

               %M  and  %m are available on only systems that store the remote
               hostname in /etc/utmp.  If unset, `%n has %a %l  from  %m.'  is
               used,  or  `%n  has  %a  %l.'  on systems which don't store the
               remote hostname.

       wordchars (+)
               A list of non-alphanumeric characters to be considered part  of
               a  word  by  the  forward-word, backward-word etc., editor com-
               mands.  If unset, `*?_-.[]~=' is used.


       AFSUSER (+)
               Equivalent to the afsuser shell variable.

       COLUMNS The number of columns in the terminal.   See  Terminal  manage-

       DISPLAY Used by X Window System (see X(1)).  If set, the shell does not
               set autologout (q.v.).

       EDITOR  The pathname to a default editor.  See also the VISUAL environ-
               ment variable and the run-fg-editor editor command.

       GROUP (+)
               Equivalent to the group shell variable.

       HOME    Equivalent to the home shell variable.

       HOST (+)
               Initialized  to  the  name of the machine on which the shell is
               running, as determined by the gethostname(2) system call.

       HOSTTYPE (+)
               Initialized to the type of machine on which the shell  is  run-
               ning, as determined at compile time.  This variable is obsolete
               and will be removed in a future version.

       HPATH (+)
               A colon-separated list of directories  in  which  the  run-help
               editor command looks for command documentation.

       LANG    Gives the preferred character environment.  See Native Language
               System support.

               If set, only ctype character handling is changed.   See  Native
               Language System support.

       LINES   The  number of lines in the terminal.  See Terminal management.

               The format of this variable is reminiscent  of  the  termcap(5)
               file  format; a colon-separated list of expressions of the form
               "xx=string", where "xx" is a two-character variable name.   The
               variables with their associated defaults are:

                   no   0      Normal (non-filename) text
                   fi   0      Regular file
                   di   01;34  Directory
                   ln   01;36  Symbolic link
                   pi   33     Named pipe (FIFO)
                   so   01;35  Socket
                   do   01;35  Door
                   bd   01;33  Block device
                   cd   01;32  Character device
                   ex   01;32  Executable file
                   mi   (none) Missing file (defaults to fi)
                   or   (none) Orphaned symbolic link (defaults to ln)
                   lc   ^[[    Left code
                   rc   m      Right code
                   ec   (none) End code (replaces lc+no+rc)

               You  need to include only the variables you want to change from
               the default.

               File names can also be colorized based on  filename  extension.
               This  is  specified  in the LS_COLORS variable using the syntax
               "*ext=string".  For example, using ISO 6429 codes, to color all
               C-language  source files blue you would specify "*.c=34".  This
               would color all files ending in .c in blue (34) color.

               Control characters can be  written  either  in  C-style-escaped
               notation,  or  in  stty-like  ^-notation.  The C-style notation
               adds ^[ for Escape, _ for a normal space character, and  ?  for
               Delete.   In  addition,  the ^[ escape character can be used to
               override the default interpretation of ^[, ^, : and =.

               Each file will be written as <lc> <color-code> <rc>  <filename>
               <ec>.   If  the  <ec> code is undefined, the sequence <lc> <no>
               <rc> will be used instead.  This is generally  more  convenient
               to  use,  but  less general.  The left, right and end codes are
               provided so you don't have to type common parts over  and  over
               again  and  to  support weird terminals; you will generally not
               need to change them at all unless your terminal  does  not  use
               ISO 6429 color sequences but a different system.

               If your terminal does use ISO 6429 color codes, you can compose
               the type codes (i.e., all except the lc, rc, and ec codes) from
               numerical  commands  separated  by semicolons.  The most common
               commands are:

                       0   to restore default color
                       1   for brighter colors
                       4   for underlined text
                       5   for flashing text
                       30  for black foreground
                       31  for red foreground
                       32  for green foreground
                       33  for yellow (or brown) foreground
                       34  for blue foreground
                       35  for purple foreground
                       36  for cyan foreground
                       37  for white (or gray) foreground
                       40  for black background
                       41  for red background
                       42  for green background
                       43  for yellow (or brown) background
                       44  for blue background
                       45  for purple background
                       46  for cyan background
                       47  for white (or gray) background

               Not all commands will work on all systems or display devices.

               A few terminal programs do not recognize the default  end  code
               properly.   If all text gets colorized after you do a directory
               listing, try changing the no and fi codes from 0 to the numeri-
               cal codes for your standard fore- and background colors.

       MACHTYPE (+)
               The  machine  type  (microprocessor class or machine model), as
               determined at compile time.

       NOREBIND (+)
               If set, printable characters are not  rebound  to  self-insert-
               command.  See Native Language System support.

       OSTYPE (+)
               The operating system, as determined at compile time.

       PATH    A colon-separated list of directories in which to look for exe-
               cutables.  Equivalent to the path shell variable, but in a dif-
               ferent format.

       PWD (+) Equivalent  to  the cwd shell variable, but not synchronized to
               it; updated only after an actual directory change.

       REMOTEHOST (+)
               The host from which the user has logged in remotely, if this is
               the  case  and  the shell is able to determine it.  Set only if
               the shell was so compiled; see the version shell variable.

       SHLVL (+)
               Equivalent to the shlvl shell variable.

       SYSTYPE (+)
               The current system type.  (Domain/OS only)

       TERM    Equivalent to the term shell variable.

       TERMCAP The terminal capability string.  See Terminal management.

       USER    Equivalent to the user shell variable.

       VENDOR (+)
               The vendor, as determined at compile time.

       VISUAL  The pathname to a default full-screen  editor.   See  also  the
               EDITOR  environment  variable and the run-fg-editor editor com-


       /etc/csh.cshrc  Read first by every shell.  ConvexOS, Stellix and Intel
                       use  /etc/cshrc  and  NeXTs  use /etc/cshrc.std.  A/UX,
                       AMIX, Cray and IRIX have no equivalent in  csh(1),  but
                       read  this  file  in tcsh anyway.  Solaris 2.x does not
                       have it either, but tcsh reads /etc/.cshrc.  (+)
       /etc/csh.login  Read by login shells after  /etc/csh.cshrc.   ConvexOS,
                       Stellix   and   Intel   use   /etc/login,   NeXTs   use
                       /etc/login.std, Solaris 2.x uses /etc/.login and  A/UX,
                       AMIX, Cray and IRIX use /etc/cshrc.
       ~/.tcshrc (+)   Read by every shell after /etc/csh.cshrc or its equiva-
       ~/.cshrc        Read by every shell, if ~/.tcshrc doesn't exist,  after
                       /etc/csh.cshrc  or  its  equivalent.   This manual uses
                       `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is  not
                       found, ~/.cshrc'.
       ~/.history      Read  by  login  shells  after ~/.tcshrc if savehist is
                       set, but see also histfile.
       ~/.login        Read by login shells  after  ~/.tcshrc  or  ~/.history.
                       The  shell  may  be  compiled  to  read ~/.login before
                       instead of after ~/.tcshrc and ~/.history; see the ver-
                       sion shell variable.
       ~/.cshdirs (+)  Read by login shells after ~/.login if savedirs is set,
                       but see also dirsfile.
       /etc/csh.logout Read by login shells at logout.  ConvexOS, Stellix  and
                       Intel  use  /etc/logout  and NeXTs use /etc/logout.std.
                       A/UX, AMIX, Cray and IRIX have no equivalent in csh(1),
                       but  read  this  file in tcsh anyway.  Solaris 2.x does
                       not have it either, but tcsh reads /etc/.logout.  (+)
       ~/.logout       Read by login shells at logout after /etc/csh.logout or
                       its equivalent.
       /bin/sh         Used  to  interpret  shell  scripts not starting with a
       /tmp/sh*        Temporary file for `<<'.
       /etc/passwd     Source of home directories for `~name' substitutions.

       The order in which startup files are read may differ if the  shell  was
       so compiled; see Startup and shutdown and the version shell variable.


       This  manual  describes tcsh as a single entity, but experienced csh(1)
       users will want to pay special attention to tcsh's new features.

       A command-line editor, which supports  GNU  Emacs  or  vi(1)-style  key
       bindings.  See The command-line editor and Editor commands.

       Programmable,  interactive word completion and listing.  See Completion
       and listing and the complete and uncomplete builtin commands.

       Spelling correction (q.v.) of filenames, commands and variables.

       Editor commands (q.v.) which perform other useful functions in the mid-
       dle of typed commands, including documentation lookup (run-help), quick
       editor restarting (run-fg-editor) and  command  resolution  (which-com-

       An  enhanced  history  mechanism.  Events in the history list are time-
       stamped.  See also the history command and its associated  shell  vari-
       ables,  the  previously  undocumented `#' event specifier and new modi-
       fiers under History substitution, the *-history,  history-search-*,  i-
       search-*,  vi-search-*  and  toggle-literal-history editor commands and
       the histlit shell variable.

       Enhanced directory parsing and directory stack handling.  See  the  cd,
       pushd, popd and dirs commands and their associated shell variables, the
       description of Directory stack substitution, the dirstack, owd and sym-
       links shell variables and the normalize-command and normalize-path edi-
       tor commands.

       Negation in glob-patterns.  See Filename substitution.

       New File inquiry operators (q.v.) and a  filetest  builtin  which  uses

       A  variety  of  Automatic,  periodic  and timed events (q.v.) including
       scheduled events, special aliases, automatic logout and terminal  lock-
       ing, command timing and watching for logins and logouts.

       Support for the Native Language System (see Native Language System sup-
       port), OS variant features (see OS variant support and  the  echo_style
       shell variable) and system-dependent file locations (see FILES).

       Extensive terminal-management capabilities.  See Terminal management.

       New  builtin  commands including builtins, hup, ls-F, newgrp, printenv,
       which and where (q.v.).

       New variables that make useful  information  easily  available  to  the
       shell.   See  the  gid, loginsh, oid, shlvl, tcsh, tty, uid and version
       shell variables and the HOST, REMOTEHOST, VENDOR, OSTYPE  and  MACHTYPE
       environment variables.

       A new syntax for including useful information in the prompt string (see
       prompt).  and special prompts for loops and  spelling  correction  (see
       prompt2 and prompt3).

       Read-only variables.  See Variable substitution.


       When  a  suspended command is restarted, the shell prints the directory
       it started in if this is different from the  current  directory.   This
       can be misleading (i.e., wrong) as the job may have changed directories

       Shell  builtin  functions  are  not   stoppable/restartable.    Command
       sequences  of the form `a ; b ; c' are also not handled gracefully when
       stopping is attempted.  If you suspend `b', the shell will then immedi-
       ately  execute  `c'.   This  is especially noticeable if this expansion
       results from an alias.  It suffices to place the sequence  of  commands
       in ()'s to force it to a subshell, i.e., `( a ; b ; c )'.

       Control  over tty output after processes are started is primitive; per-
       haps this will inspire someone to  work  on  a  good  virtual  terminal
       interface.   In  a  virtual  terminal  interface  much more interesting
       things could be done with output control.

       Alias substitution is most often used to clumsily simulate shell proce-
       dures; shell procedures should be provided rather than aliases.

       Commands  within  loops  are  not  placed in the history list.  Control
       structures should be parsed rather than being  recognized  as  built-in
       commands.   This would allow control commands to be placed anywhere, to
       be combined with `|', and to be used with `&' and `;' metasyntax.

       foreach doesn't ignore here documents when looking for its end.

       It should be possible to use the `:' modifiers on the output of command

       The  screen  update for lines longer than the screen width is very poor
       if the terminal cannot move the cursor up (i.e., terminal type `dumb').

       HPATH and NOREBIND don't need to be environment variables.

       Glob-patterns  which  do  not use `?', `*' or `[]' or which use `{}' or
       `~' are not negated correctly.

       The single-command form of if  does  output  redirection  even  if  the
       expression is false and the command is not executed.

       ls-F includes file identification characters when sorting filenames and
       does not handle control characters in filenames  well.   It  cannot  be

       Command substitution supports multiple commands and conditions, but not
       cycles or backward gotos.

       Report bugs at, preferably with fixes.  If you want
       to  help  maintain  and  test tcsh, send mail to
       with the text `subscribe tcsh' on a line by itself in the body.


       In 1964, DEC produced the PDP-6.  The PDP-10 was a later re-implementa-
       tion.   It  was  re-christened  the DECsystem-10 in 1970 or so when DEC
       brought out the second model, the KI10.

       TENEX was created at Bolt, Beranek & Newman (a Cambridge, Massachusetts
       think  tank)  in  1972  as an experiment in demand-paged virtual memory
       operating systems.  They built a new pager for the DEC PDP-10 and  cre-
       ated the OS to go with it.  It was extremely successful in academia.

       In  1975,  DEC  brought  out  a new model of the PDP-10, the KL10; they
       intended to have only a version of TENEX, which they had licensed  from
       BBN,  for  the new box.  They called their version TOPS-20 (their capi-
       talization is trademarked).  A lot of  TOPS-10  users  (`The  OPerating
       System  for PDP-10') objected; thus DEC found themselves supporting two
       incompatible systems on the same hardware--but then there were 6 on the

       TENEX,  and  TOPS-20  to  version 3, had command completion via a user-
       code-level subroutine library called ULTCMD.  With version 3, DEC moved
       all  that  capability  and more into the monitor (`kernel' for you Unix
       types), accessed by the COMND% JSYS (`Jump to SYStem' instruction,  the
       supervisor call mechanism [are my IBM roots also showing?]).

       The creator of tcsh was impressed by this feature and several others of
       TENEX and TOPS-20, and created a version of csh which mimicked them.


       Words can be no longer than 1024 characters.

       The system limits argument lists to 10240 characters.

       The number of arguments to a command which involves filename  expansion
       is  limited  to  1/6th  the number of characters allowed in an argument

       Command substitutions  may  substitute  no  more  characters  than  are
       allowed in an argument list.

       To  detect  looping,  the shell restricts the number of alias substitu-
       tions on a single line to 20.


       csh(1), emacs(1), ls(1), newgrp(1), sh(1), setpath(1), stty(1),  su(1),
       tset(1),   vi(1),   x(1),  access(2),  execve(2),  fork(2),  killpg(2),
       pipe(2), setrlimit(2), sigvec(2), stat(2), umask(2), vfork(2), wait(2),
       malloc(3),  setlocale(3),  tty(4),  a.out(5),  termcap(5),  environ(7),
       termio(7), Introduction to the C Shell


       This manual documents tcsh 6.15.00 (Astron) 2007-03-03.


       William Joy
         Original author of csh(1)
       J.E. Kulp, IIASA, Laxenburg, Austria
         Job control and directory stack features
       Ken Greer, HP Labs, 1981
         File name completion
       Mike Ellis, Fairchild, 1983
         Command name recognition/completion
       Paul Placeway, Ohio State CIS Dept., 1983-1993
         Command line editor, prompt routines, new glob  syntax  and  numerous
         fixes and speedups
       Karl Kleinpaste, CCI 1983-4
         Special  aliases,  directory  stack  extraction  stuff,  login/logout
         watch, scheduled events, and the idea of the new prompt format
       Rayan Zachariassen, University of Toronto, 1984
         ls-F and which builtins and numerous  bug  fixes,  modifications  and
       Chris Kingsley, Caltech
         Fast storage allocator routines
       Chris Grevstad, TRW, 1987
         Incorporated 4.3BSD csh into tcsh
       Christos S. Zoulas, Cornell U. EE Dept., 1987-94
         Ports   to   HPUX,   SVR2  and  SVR3,  a  SysV  version  of  getwd.c,
         SHORT_STRINGS support and a new version of sh.glob.c
       James J Dempsey, BBN, and Paul Placeway, OSU, 1988
         A/UX port
       Daniel Long, NNSC, 1988
       Patrick Wolfe, Kuck and Associates, Inc., 1988
         vi mode cleanup
       David C Lawrence, Rensselaer Polytechnic Institute, 1989
         autolist and ambiguous completion listing
       Alec Wolman, DEC, 1989
         Newlines in the prompt
       Matt Landau, BBN, 1989
       Ray Moody, Purdue Physics, 1989
         Magic space bar history expansion
       Mordechai ????, Intel, 1989
         printprompt() fixes and additions
       Kazuhiro Honda, Dept. of Computer Science, Keio University, 1989
         Automatic spelling correction and prompt3
       Per Hedeland, Ellemtel, Sweden, 1990-
         Various bugfixes, improvements and manual updates
       Hans J. Albertsson (Sun Sweden)
         ampm, settc and telltc
       Michael Bloom
         Interrupt handling fixes
       Michael Fine, Digital Equipment Corp
         Extended key support
       Eric Schnoebelen, Convex, 1990
         Convex support, lots of csh bug fixes, save and restore of  directory
       Ron Flax, Apple, 1990
         A/UX 2.0 (re)port
       Dan Oscarsson, LTH Sweden, 1990
         NLS support and simulated NLS support for non NLS sites, fixes
       Johan Widen, SICS Sweden, 1990
         shlvl, Mach support, correct-line, 8-bit printing
       Matt Day, Sanyo Icon, 1990
         POSIX termio support, SysV limit fixes
       Jaap Vermeulen, Sequent, 1990-91
         Vi mode fixes, expand-line, window change fixes, Symmetry port
       Martin Boyer, Institut de recherche d'Hydro-Quebec, 1991
         autolist  beeping  options, modified the history search to search for
         the whole string from the beginning of the line to the cursor.
       Scott Krotz, Motorola, 1991
         Minix port
       David Dawes, Sydney U. Australia, Physics Dept., 1991
         SVR4 job control fixes
       Jose Sousa, Interactive Systems Corp., 1991
         Extended vi fixes and vi delete command
       Marc Horowitz, MIT, 1991
         ANSIfication fixes, new exec hashing code, imake fixes, where
       Bruce Sterling Woodcock,, 1991-1995
         ETA and Pyramid port, Makefile and lint fixes, ignoreeof=n  addition,
         and various other portability changes and bug fixes
       Jeff Fink, 1992
         complete-word-fwd and complete-word-back
       Harry C. Pulley, 1992
         Coherent port
       Andy Phillips, Mullard Space Science Lab U.K., 1992
         VMS-POSIX port
       Beto Appleton, IBM Corp., 1992
         Walking  process  group fixes, csh bug fixes, POSIX file tests, POSIX
       Scott Bolte, Cray Computer Corp., 1992
         CSOS port
       Kaveh R. Ghazi, Rutgers University, 1992
         Tek, m88k, Titan and Masscomp ports and fixes.  Added  autoconf  sup-
       Mark Linderman, Cornell University, 1992
         OS/2 port
       Mika Liljeberg, liljeber@kruuna.Helsinki.FI, 1992
         Linux port
       Tim P. Starrin, NASA Langley Research Center Operations, 1993
         Read-only variables
       Dave Schweisguth, Yale University, 1993-4
         New man page and tcsh.man2html
       Larry Schwimmer, Stanford University, 1993
         AFS and HESIOD patches
       Luke Mewburn, RMIT University, 1994-6
         Enhanced directory printing in prompt, added ellipsis and rprompt.
       Edward Hutchins, Silicon Graphics Inc., 1996
         Added implicit cd.
       Martin Kraemer, 1997
         Ported to Siemens Nixdorf EBCDIC machine
       Amol Deshpande, Microsoft, 1997
         Ported  to  WIN32  (Windows/95 and Windows/NT); wrote all the missing
         library and message catalog code to interface to Windows.
       Taga Nayuta, 1998
         Color ls additions.


       Bryan Dunlap, Clayton Elwell, Karl Kleinpaste, Bob Manson, Steve Romig,
       Diana  Smetters, Bob Sutterfield, Mark Verber, Elizabeth Zwicky and all
       the other people at Ohio State for suggestions and encouragement

       All the people on the net, for putting up with, reporting bugs in,  and
       suggesting new additions to each and every version

       Richard M. Alderson III, for writing the `T in tcsh' section

Astron 6.15.00                   3 March 2007                          tcsh(1)

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