File: grep.info,  Node: File and Directory Selection,  Next: Other Options,  Prev: Context Line Control,  Up: Command-line Options

2.1.6 File and Directory Selection
----------------------------------

‘-a’
‘--text’
     Process a binary file as if it were text; this is equivalent to the
     ‘--binary-files=text’ option.

‘--binary-files=TYPE’
     If a file's data or metadata indicate that the file contains binary
     data, assume that the file is of type TYPE.  Non-text bytes
     indicate binary data; these are either output bytes that are
     improperly encoded for the current locale (*note Environment
     Variables::), or null input bytes when the ‘-z’ (‘--null-data’)
     option is not given (*note Other Options::).

     By default, TYPE is ‘binary’, and ‘grep’ suppresses output after
     null input binary data is discovered, and suppresses output lines
     that contain improperly encoded data.  When some output is
     suppressed, ‘grep’ follows any output with a message to standard
     error saying that a binary file matches.

     If TYPE is ‘without-match’, when ‘grep’ discovers null input binary
     data it assumes that the rest of the file does not match; this is
     equivalent to the ‘-I’ option.

     If TYPE is ‘text’, ‘grep’ processes binary data as if it were text;
     this is equivalent to the ‘-a’ option.

     When TYPE is ‘binary’, ‘grep’ may treat non-text bytes as line
     terminators even without the ‘-z’ (‘--null-data’) option.  This
     means choosing ‘binary’ versus ‘text’ can affect whether a pattern
     matches a file.  For example, when TYPE is ‘binary’ the pattern
     ‘q$’ might match ‘q’ immediately followed by a null byte, even
     though this is not matched when TYPE is ‘text’.  Conversely, when
     TYPE is ‘binary’ the pattern ‘.’ (period) might not match a null
     byte.

     _Warning:_ The ‘-a’ (‘--binary-files=text’) option might output
     binary garbage, which can have nasty side effects if the output is
     a terminal and if the terminal driver interprets some of it as
     commands.  On the other hand, when reading files whose text
     encodings are unknown, it can be helpful to use ‘-a’ or to set
     ‘LC_ALL='C'’ in the environment, in order to find more matches even
     if the matches are unsafe for direct display.

‘-D ACTION’
‘--devices=ACTION’
     If an input file is a device, FIFO, or socket, use ACTION to
     process it.  If ACTION is ‘read’, all devices are read just as if
     they were ordinary files.  If ACTION is ‘skip’, devices, FIFOs, and
     sockets are silently skipped.  By default, devices are read if they
     are on the command line or if the ‘-R’ (‘--dereference-recursive’)
     option is used, and are skipped if they are encountered recursively
     and the ‘-r’ (‘--recursive’) option is used.  This option has no
     effect on a file that is read via standard input.

‘-d ACTION’
‘--directories=ACTION’
     If an input file is a directory, use ACTION to process it.  By
     default, ACTION is ‘read’, which means that directories are read
     just as if they were ordinary files (some operating systems and
     file systems disallow this, and will cause ‘grep’ to print error
     messages for every directory or silently skip them).  If ACTION is
     ‘skip’, directories are silently skipped.  If ACTION is ‘recurse’,
     ‘grep’ reads all files under each directory, recursively, following
     command-line symbolic links and skipping other symlinks; this is
     equivalent to the ‘-r’ option.

‘--exclude=GLOB’
     Skip any command-line file with a name suffix that matches the
     pattern GLOB, using wildcard matching; a name suffix is either the
     whole name, or a trailing part that starts with a non-slash
     character immediately after a slash (‘/’) in the name.  When
     searching recursively, skip any subfile whose base name matches
     GLOB; the base name is the part after the last slash.  A pattern
     can use ‘*’, ‘?’, and ‘[’...‘]’  as wildcards, and ‘\’ to quote a
     wildcard or backslash character literally.

‘--exclude-from=FILE’
     Skip files whose name matches any of the patterns read from FILE
     (using wildcard matching as described under ‘--exclude’).

‘--exclude-dir=GLOB’
     Skip any command-line directory with a name suffix that matches the
     pattern GLOB.  When searching recursively, skip any subdirectory
     whose base name matches GLOB.  Ignore any redundant trailing
     slashes in GLOB.

‘-I’
     Process a binary file as if it did not contain matching data; this
     is equivalent to the ‘--binary-files=without-match’ option.

‘--include=GLOB’
     Search only files whose name matches GLOB, using wildcard matching
     as described under ‘--exclude’.  If contradictory ‘--include’ and
     ‘--exclude’ options are given, the last matching one wins.  If no
     ‘--include’ or ‘--exclude’ options match, a file is included unless
     the first such option is ‘--include’.

‘-r’
‘--recursive’
     For each directory operand, read and process all files in that
     directory, recursively.  Follow symbolic links on the command line,
     but skip symlinks that are encountered recursively.  Note that if
     no file operand is given, grep searches the working directory.
     This is the same as the ‘--directories=recurse’ option.

‘-R’
‘--dereference-recursive’
     For each directory operand, read and process all files in that
     directory, recursively, following all symbolic links.