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10.8 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 ‘afs’. 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 a custom version originally derived from the 4.2 BSD malloc. This malloc is very fast, but wastes some space on each allocation, though it uses several techniques to minimize the waste. 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. configure usually chooses this automatically, since most systems include the termcap functions in the curses library.

--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). The Bash default is to link with a static library built in the lib/readline subdirectory of the build directory.

--with-libintl-prefix[=PREFIX]

Define this to make Bash link with a locally-installed version of the libintl library instead of the version in lib/intl.

--with-libiconv-prefix[=PREFIX]

Define this to make Bash look for libiconv in PREFIX instead of the standard system locations. The Bash distribution does not include this library.

--enable-minimal-config

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

There are several --enable- options that alter how Bash is compiled, linked, and installed, 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-separate-helpfiles

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

--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 ‘alt-array-implementation’, ‘disabled-builtins’, ‘direxpand-default’, ‘strict-posix-default’, 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 Aliases).

--enable-alt-array-implementation

This builds Bash using an alternate implementation of arrays (see Arrays) that provides faster access at the expense of using more memory (sometimes many times more, depending on how sparse an array is).

--enable-arith-for-command

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

--enable-array-variables

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

--enable-bang-history

Include support for csh-like history substitution (see History Expansion).

--enable-bash-source-fullpath-default

Set the default value of the bash_source_fullpath shell option described above under The Shopt Builtin to be enabled. This controls how filenames are assigned to the BASH_SOURCE array variable.

--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 Pipelines). This allows timing pipelines, shell compound commands, shell builtins, and shell functions, which an external command cannot do easily.

--enable-cond-command

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

--enable-cond-regexp

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

--enable-coprocesses

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

--enable-debugger

Include support for the Bash debugger (distributed separately).

--enable-dev-fd-stat-broken

If calling stat on /dev/fd/N returns different results than calling fstat on file descriptor N, supply this option to enable a workaround. This has implications for conditional commands that test file attributes.

--enable-direxpand-default

Cause the direxpand shell option (see The Shopt Builtin) to be enabled by default when the shell starts. It is normally disabled by default.

--enable-directory-stack

Include support for a csh-like directory stack and the pushd, popd, and dirs builtins (see 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 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-function-import

Include support for importing function definitions exported by another instance of the shell from the environment. This option is enabled by default.

--enable-glob-asciiranges-default

Set the default value of the globasciiranges shell option described above under The Shopt Builtin to be enabled. This controls the behavior of character ranges when used in pattern matching bracket expressions.

--enable-help-builtin

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

--enable-history

Include command history and the fc and history builtin commands (see Bash History Facilities).

--enable-job-control

This enables the job control features (see 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 Redirections).

--enable-process-substitution

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

--enable-progcomp

Enable the programmable completion facilities (see 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 $PS0, $PS1, $PS2, 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 (see Command Line Editing).

--enable-restricted

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

--enable-select

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

--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 Bash and POSIX).

--enable-translatable-strings

Enable support for $"string" translatable strings (see Locale-Specific Translation).

--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 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.