8.8 Optional Features

The Bash configure has a number of ‘--enable-feature’ options, where feature indicates an optional part of Bash. There are also several ‘--with-package’ options, where package is something like ‘bash-malloc’ or ‘purify’. To turn off the default use of a package, use ‘--without-package’. To configure Bash without a feature that is enabled by default, use ‘--disable-feature’.

Here is a complete list of the ‘--enable-’ and ‘--with-’ options that the Bash configure recognizes.

--with-afs

Define if you are using the Andrew File System from Transarc.

--with-bash-malloc

Use the Bash version of malloc in the directory ‘lib/malloc’. This is not the same malloc that appears in GNU libc, but an older version originally derived from the 4.2 BSD malloc. This malloc is very fast, but wastes some space on each allocation. This option is enabled by default. The ‘NOTES’ file contains a list of systems for which this should be turned off, and configure disables this option automatically for a number of systems.

--with-curses

Use the curses library instead of the termcap library. This should be supplied if your system has an inadequate or incomplete termcap database.

--with-gnu-malloc

A synonym for --with-bash-malloc.

--with-installed-readline[=PREFIX]

Define this to make Bash link with a locally-installed version of Readline rather than the version in ‘lib/readline’. This works only with Readline 5.0 and later versions. If PREFIX is yes or not supplied, configure uses the values of the make variables includedir and libdir, which are subdirectories of prefix by default, to find the installed version of Readline if it is not in the standard system include and library directories. If PREFIX is no, Bash links with the version in ‘lib/readline’. If PREFIX is set to any other value, configure treats it as a directory pathname and looks for the installed version of Readline in subdirectories of that directory (include files in PREFIX/include and the library in PREFIX/lib).

--with-purify

Define this to use the Purify memory allocation checker from Rational Software.

--enable-minimal-config

This produces a shell with minimal features, close to the historical Bourne shell.

There are several ‘--enable-’ options that alter how Bash is compiled and linked, rather than changing run-time features.

--enable-largefile

Enable support for large files if the operating system requires special compiler options to build programs which can access large files. This is enabled by default, if the operating system provides large file support.

--enable-profiling

This builds a Bash binary that produces profiling information to be processed by gprof each time it is executed.

--enable-static-link

This causes Bash to be linked statically, if gcc is being used. This could be used to build a version to use as root’s shell.

The ‘minimal-config’ option can be used to disable all of the following options, but it is processed first, so individual options may be enabled using ‘enable-feature’.

All of the following options except for ‘disabled-builtins’ and ‘xpg-echo-default’ are enabled by default, unless the operating system does not provide the necessary support.

--enable-alias

Allow alias expansion and include the alias and unalias builtins (see section Aliases).

--enable-arith-for-command

Include support for the alternate form of the for command that behaves like the C language for statement (see section Looping Constructs).

--enable-array-variables

Include support for one-dimensional array shell variables (see section Arrays).

--enable-bang-history

Include support for csh-like history substitution (@pxref{History Interaction}).

--enable-brace-expansion

Include csh-like brace expansion ( b{a,b}c → bac bbc ). See Brace Expansion, for a complete description.

--enable-casemod-attributes

Include support for case-modifying attributes in the declare builtin and assignment statements. Variables with the uppercase attribute, for example, will have their values converted to uppercase upon assignment.

--enable-casemod-expansion

Include support for case-modifying word expansions.

--enable-command-timing

Include support for recognizing time as a reserved word and for displaying timing statistics for the pipeline following time (see section Pipelines). This allows pipelines as well as shell builtins and functions to be timed.

--enable-cond-command

Include support for the [[ conditional command. (see section Conditional Constructs).

--enable-cond-regexp

Include support for matching POSIX regular expressions using the ‘=~’ binary operator in the [[ conditional command. (see section Conditional Constructs).

--enable-coprocesses

Include support for coprocesses and the coproc reserved word (see section Pipelines).

--enable-debugger

Include support for the bash debugger (distributed separately).

--enable-directory-stack

Include support for a csh-like directory stack and the pushd, popd, and dirs builtins (see section The Directory Stack).

--enable-disabled-builtins

Allow builtin commands to be invoked via ‘builtin xxx’ even after xxx has been disabled using ‘enable -n xxx’. See Bash Builtin Commands, for details of the builtin and enable builtin commands.

--enable-dparen-arithmetic

Include support for the ((…)) command (see section Conditional Constructs).

--enable-extended-glob

Include support for the extended pattern matching features described above under Pattern Matching.

--enable-extended-glob-default

Set the default value of the extglob shell option described above under The Shopt Builtin to be enabled.

--enable-help-builtin

Include the help builtin, which displays help on shell builtins and variables (see section Bash Builtin Commands).

--enable-history

Include command history and the fc and history builtin commands (@pxref{Bash History Facilities}).

--enable-job-control

This enables the job control features (see section Job Control), if the operating system supports them.

--enable-multibyte

This enables support for multibyte characters if the operating system provides the necessary support.

--enable-net-redirections

This enables the special handling of filenames of the form /dev/tcp/host/port and /dev/udp/host/port when used in redirections (see section Redirections).

--enable-process-substitution

This enables process substitution (see section Process Substitution) if the operating system provides the necessary support.

--enable-progcomp

Enable the programmable completion facilities (@pxref{Programmable Completion}). If Readline is not enabled, this option has no effect.

--enable-prompt-string-decoding

Turn on the interpretation of a number of backslash-escaped characters in the $PS1, $PS2, $PS3, and $PS4 prompt strings. See Controlling the Prompt, for a complete list of prompt string escape sequences.

--enable-readline

Include support for command-line editing and history with the Bash version of the Readline library (@pxref{Command Line Editing}).

--enable-restricted

Include support for a restricted shell. If this is enabled, Bash, when called as rbash, enters a restricted mode. See The Restricted Shell, for a description of restricted mode.

--enable-select

Include the select compound command, which allows the generation of simple menus (see section Conditional Constructs).

--enable-separate-helpfiles

Use external files for the documentation displayed by the help builtin instead of storing the text internally.

--enable-single-help-strings

Store the text displayed by the help builtin as a single string for each help topic. This aids in translating the text to different languages. You may need to disable this if your compiler cannot handle very long string literals.

--enable-strict-posix-default

Make Bash POSIX-conformant by default (see section Bash POSIX Mode).

--enable-usg-echo-default

A synonym for --enable-xpg-echo-default.

--enable-xpg-echo-default

Make the echo builtin expand backslash-escaped characters by default, without requiring the ‘-e’ option. This sets the default value of the xpg_echo shell option to on, which makes the Bash echo behave more like the version specified in the Single Unix Specification, version 3. See section Bash Builtin Commands, for a description of the escape sequences that echo recognizes.

The file ‘config-top.h’ contains C Preprocessor ‘#define’ statements for options which are not settable from configure. Some of these are not meant to be changed; beware of the consequences if you do. Read the comments associated with each definition for more information about its effect.