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bash-hackers-wiki/docs/internals/shell_options.md

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---
tags:
- bash
- shell
- scripting
- options
- runtime
- variable
- behaviour
---
# List of shell options
This information was taken from a Bash version "`4.1`", every now and
then new options are added, so likely, this list isn't complete.
The shell-options can be set with the [shopt builtin
command](../commands/builtin/shopt.md).
## Shell options
### autocd
| Option: | `autocd` | Since: | 4.0-alpha |
|:------------|:-----------------|:---------|:----------|
| Shell mode: | interactive only | Default: | off |
If set, a command name that is the name of a directory is executed as if
it were the argument to the cd command.
### assoc_expand_once
| Option: | `assoc_expand_once` | Since: | 5.0-alpha |
|:------------|:--------------------|:---------|:----------|
| Shell mode: | all | Default: | off |
If set, Bash attempts to expand associative array options only once.
### cdable_vars
| Option: | `cdable_vars` | Since: | unknown |
|:------------|:--------------|:---------|:--------|
| Shell mode: | all | Default: | off |
Treat every **non-directory argument** to the `cd`-command as variable
name containing a directory to `cd` into.
### cdspell
| Option: | `cdspell` | Since: | unknown |
|:------------|:-----------------|:---------|:--------|
| Shell mode: | interactive only | Default: | off |
If set, minor errors in the spelling of a directory component in a cd
command will be corrected. The errors checked for are transposed
characters, a missing character, and one character too many. If a
correction is found, the corrected file name is printed, and the command
proceeds.
### checkhash
| Option: | `checkhash` | Since: | unknown |
|:------------|:------------|:---------|:--------|
| Shell mode: | all | Default: | off |
If set, Bash checks that a command found in the hash table exists before
trying to execute it. If a hashed command no longer exists, a normal
path search is performed.
### checkjobs
| Option: | `checkjobs` | Since: | 4.0-alpha |
|:------------|:-----------------|:---------|:----------|
| Shell mode: | interactive only | Default: | off |
If set, Bash lists the status of any stopped and running jobs before
exiting an interactive shell. If any jobs are running, this causes the
exit to be deferred until a second exit is attempted without an
intervening command. The shell always postpones exiting if any jobs are
stopped.
### checkwinsize
| Option: | `checkwinsize` | Since: | unknown |
|:------------|:---------------|:---------|:--------|
| Shell mode: | all | Default: | on |
If set, Bash checks the window size after each command and, if
necessary, updates the values of the variables
[LINES](../syntax/shellvars.md#LINES) and
[COLUMNS](../syntax/shellvars.md#COLUMNS).
### cmdhist
| Option: | `cmdhist` | Since: | unknown |
|:------------|:----------|:---------|:--------|
| Shell mode: | all | Default: | off |
If set, Bash attempts to save all lines of a multiple-line command in
the same history entry. This allows easy re-editing of multi-line
commands.
### compat31
| Option: | `compat31` | Since: | 3.2 |
|:------------|:-----------|:---------|:----|
| Shell mode: | all | Default: | off |
Compatiblity mode for Bash 3.1
### compat32
| Option: | `compat32` | Since: | 4.0 |
|:------------|:-----------|:---------|:----|
| Shell mode: | all | Default: | off |
Compatiblity mode for Bash 3.2
### compat40
| Option: | `compat40` | Since: | 4.1-beta |
|:------------|:-----------|:---------|:---------|
| Shell mode: | all | Default: | off |
Compatiblity mode for Bash 4.0
### compat41
| Option: | `compat41` | Since: | 4.2-alpha |
|:------------|:-----------|:---------|:----------|
| Shell mode: | all | Default: | off |
Compatiblity mode for Bash 4.1
### compat42
| Option: | `compat42` | Since: | 4.3-alpha |
|:------------|:-----------|:---------|:----------|
| Shell mode: | all | Default: | off |
Compatiblity mode for Bash 4.2
### compat43
| Option: | `compat43` | Since: | 4.4-alpha |
|:------------|:-----------|:---------|:----------|
| Shell mode: | all | Default: | off |
Compatiblity mode for Bash 4.3
### compat44
| Option: | `compat44` | Since: | 5.0-alpha |
|:------------|:-----------|:---------|:----------|
| Shell mode: | all | Default: | off |
Compatiblity mode for Bash 4.4
### direxpand
| Option: | `direxpand` | Since: | 4.3-alpha |
|:------------|:------------|:---------|:-----------------------------------------------------------------------|
| Shell mode: | all | Default: | off (unless changed on compile-time with `--enable-direxpand-default`) |
If set, bash replaces directory names with the results of word expansion
when performing filename completion. This changes the contents of the
readline editing buffer. If not set, bash attempts to preserve what the
user typed.
### dirspell
| Option: | `dirspell` | Since: | 4.0-alpha |
|:------------|:-----------|:---------|:----------|
| Shell mode: | all | Default: | off |
If set, Bash will perform spelling corrections on directory names to
match a glob.
### dotglob
| Option: | `dotglob` | Since: | unknown |
|:------------|:----------|:---------|:--------|
| Shell mode: | all | Default: | off |
If set, Bash includes filenames beginning with a `.` (dot) in the
results of [pathname expansion](../syntax/expansion/globs.md).
### execfail
| Option: | `execfail` | Since: | unknown |
|:------------|:----------------|:---------|:--------|
| Shell mode: | non-interactive | Default: | off |
If set, a non-interactive shell will not exit if it cannot execute the
file specified as an argument to the `exec`-builtin command. An
interactive shell does not exit if `exec` fails.
### expand_aliases
| Option: | `expand_aliases` | Since: | unknown |
|:------------|:-----------------|:---------|:----------------------------------------|
| Shell mode: | all | Default: | on (interactive), off (non-interactive) |
If set, aliases are expanded. This option is enabled by default for
interactive shells.
### extdebug
| Option: | `extdebug` | Since: | 3.0-alpha |
|:------------|:-----------|:---------|:----------|
| Shell mode: | all | Default: | off |
If set, behavior intended for use by debuggers is enabled.
### extglob
| Option: | `extglob` | Since: | 2.02-alpha1 |
|:------------|:----------|:---------|:------------|
| Shell mode: | all | Default: | off |
If set, the extended [pattern matching](../syntax/pattern.md) features are
enabled. See the important note below under [Parser
configurations](#parser_configurations).
### extquote
| Option: | `extquote` | Since: | 3.0-alpha (?) |
|:------------|:-----------|:---------|:--------------|
| Shell mode: | all | Default: | on |
If set, `$'string'` and `$"string"` quoting is performed within
[parameter expansions](../syntax/pe.md) enclosed in double quotes. See the
important note below under [Parser
configurations](#parser_configurations).
### failglob
| Option: | `failglob` | Since: | 3.0-alpha |
|:------------|:-----------|:---------|:----------|
| Shell mode: | all | Default: | off |
If set, patterns which fail to match filenames during pathname expansion
result in an error message.
### force_fignore
| Option: | `force_fignore` | Since: | 3.0-alpha |
|:------------|:----------------|:---------|:----------|
| Shell mode: | interactive | Default: | on |
If set, the suffixes specified by the
[FIGNORE](../syntax/shellvars.md#FIGNORE) shell variable cause words to be
ignored when performing word completion even if the ignored words are
the only possible completions. This option is enabled by default.
### globasciiranges
| Option: | `globasciiranges` | Since: | 4.3-alpha |
|:------------|:------------------|:---------|:----------------------------------|
| Shell mode: | all | Default: | on (configurable at compile time) |
If set, range expressions used in pattern matching behave as if in the
traditional C locale when performing comparisons. That is, the current
locale's collating sequence is not taken into account, so b will not
collate between A and B, and upper-case and lower-case ASCII characters
will collate together.
### globstar
| Option: | `globstar` | Since: | 4.0-alpha |
|:------------|:-----------|:---------|:----------|
| Shell mode: | all | Default: | off |
If set, recursive globbing with `**` is enabled.
### gnu_errfmt
| Option: | `gnu_errfmt` | Since: | 3.0-alpha |
|:------------|:-------------|:---------|:----------|
| Shell mode: | all | Default: | off |
If set, shell error messages are written in the "standard GNU error
message format".
### histappend
| Option: | `histappend` | Since: | unknown |
|:------------|:----------------|:---------|:--------|
| Shell mode: | interactive (?) | Default: | off |
If set, the history list is appended to the file named by the value of
the [HISTFILE](../syntax/shellvars.md#HISTFILE) variable when the shell
exits, rather than overwriting the file.
### histreedit
| Option: | `histreedit` | Since: | unknown |
|:------------|:----------------|:---------|:--------|
| Shell mode: | interactive (?) | Default: | off |
If set, and readline is being used, a user is given the opportunity to
re-edit a failed history substitution.
### histverify
| Option: | `histverify` | Since: | unknown |
|:------------|:----------------|:---------|:--------|
| Shell mode: | interactive (?) | Default: | off |
Allow to review a history substitution result by loading the resulting
line into the editing buffer, rather than directly executing it.
### hostcomplete
| Option: | `hostcomplete` | Since: | 2.0-alpha3 |
|:------------|:----------------|:---------|:-----------|
| Shell mode: | interactive (?) | Default: | on |
If set, Bash completion also completes hostnames. On by default.
### huponexit
| Option: | `huponexit` | Since: | 2.02-alpha1 |
|:------------|:------------------|:---------|:------------|
| Shell mode: | interactive login | Default: | off |
If set, Bash will send the `SIGHUP` signal to all jobs when an
interactive login shell exits.
### interactive_comments
| Option: | `interactive_comments` | Since: | unknown |
|:------------|:-----------------------|:---------|:--------|
| Shell mode: | interactive | Default: | on |
Allow [commenting](../scripting/basics.md#comments) in interactive shells, on
by default.
### lastpipe
| Option: | `lastpipe` | Since: | 4.2-alpha |
|:------------|:-----------|:---------|:----------|
| Shell mode: | all | Default: | off |
If set, **and job control is not active**, the shell runs the last
command of a pipeline not executed in the background in the current
shell environment.
### lithist
| Option: | `lithist` | Since: | unknown |
|:------------|:------------|:---------|:--------|
| Shell mode: | interactive | Default: | off |
If set, and the [#cmdhist](#cmdhist) option is enabled, multi-line
commands are saved to the history with embedded newlines rather than
using semicolon separators where possible.
### localvar_inherit
| Option: | `localvar_inherit` | Since: | 5.0-alpha |
|:------------|:-------------------|:---------|:----------|
| Shell mode: | all | Default: | off |
If this option is set, a local variable inherits the value of a variable
with the same name at the nearest preceding scope.
### login_shell
| Option: | `login_shell` | Since: | 2.05a-alpha1 |
|:------------|:--------------|:---------|:-------------|
| Shell mode: | all | Default: | n/a |
The option is set when Bash is a login shell. This is a readonly option.
### mailwarn
| Option: | `mailwarn` | Since: | unknown |
|:------------|:----------------|:---------|:--------|
| Shell mode: | interactive (?) | Default: | off |
If set, and a file that Bash is checking for mail has been accessed
since the last time it was checked, the message "The mail in mailfile
has been read" is displayed.
### no_empty_cmd_completion
| Option: | `mailwarn` | Since: | unknown |
|:------------|:----------------|:---------|:--------|
| Shell mode: | interactive (?) | Default: | off |
If set, and readline is being used, Bash will not attempt to search the
PATH for possible completions when completion is attempted on an empty
line.
### nocaseglob
| Option: | `nocaseglob` | Since: | 2.02-alpha1 |
|:------------|:-------------|:---------|:------------|
| Shell mode: | all | Default: | off |
If set, Bash matches filenames in a case-insensitive fashion when
performing pathname expansion.
### nocasematch
| Option: | `nocasematch` | Since: | 3.1-alpha1 |
|:------------|:--------------|:---------|:-----------|
| Shell mode: | all | Default: | off |
If set, Bash matches patterns in a case-insensitive fashion when
performing matching while executing `case` or `[[` conditional commands.
### nullglob
| Option: | `nullglob` | Since: | unknown |
|:------------|:-----------|:---------|:--------|
| Shell mode: | all | Default: | off |
If set, Bash allows patterns which match no files to expand to a null
string, rather than themselves.
### progcomp
|Option:|`progcomp`|Since:|2.04-alpha1|
|-------|----------|------|----------|
|Shell mode:|interactive (?)|Default:|on|
If set, the programmable completion facilities are enabled. This option
is enabled by default.
### promptvars
|Option:|`promptvars`|Since:|unknown|
|-------|------------|------|-------|
|Shell mode:|interactive|Default:|on|
If set, prompt strings undergo parameter expansion, command
substitution, arithmetic expansion, and quote removal after being
expanded using the prompt special sequences. This option is enabled by
default.
### restricted_shell
|Option:|`restricted_shell`|Since:|2.03-alpha|
|-------|------------------|------|-------|
|Shell mode:|interactive (?)|Default:|off|
The option is set when Bash is a restricted shell. This is a readonly
option.
### shift_verbose
|Option:|`shift_verbose`|Since:|unknown|
|-------|---------------|------|-------|
|Shell mode:|all|Default:|off, on in POSIX mode|
If set, the shift builtin prints an error message when the shift count
exceeds the number of positional parameters.
### sourcepath
|Option:|`sourcepath`|Since:|unknown|
|-------|------------|------|-------|
|Shell mode:|all|Default:|on|
If set, the source builtin command uses the value of PATH to find the
directory containing the file supplied as an argument. This option is
enabled by default.
### syslog_history
|Option:|`syslog_history`|Since:|5.0-alpha|
|-------|----------------|------|--------|
|Shell mode:|unknown|Default:|off|
If set, the shell history is sent to syslog.
This option is undocumented and available only if the shell supports
syslog.
### xpg_echo
|Option:|`xpg_echo`|Since:|2.04-beta1|
|-------|----------|------|----------|
|Shell mode:|all|Default:|off|
If set, the `echo`-builtin command expands backslash-escape sequences by
default (POSIX, SUS, XPG).
## Parser configurations
Parser configurations change the way the Bash parser recognizes the
syntax when parsing a line. This, of course, is impossible for a line
that already was parsed.
There are two options that influence the parsing this way:
- `extglob`
- `extquote`
Consequence: You **can't** use the new syntax (e.g. the extended
globbing syntax) and the command to enable it **in the same line**.
$ shopt -s extglob; echo !(*.txt) # this is the WRONG way!
-bash: syntax error near unexpected token `('
You have to configure the parser **before** a line with new syntax is
parsed:
$ shopt -s extglob # standalone - CORRECT way!
$ echo !(*.txt)
...
## See also
- Internal: [shopt builtin command](../commands/builtin/shopt.md)
- Internal: [set builtin command](../commands/builtin/set.md)
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