shopt [-pqsu] [-o] [optname ...]
Toggle the values of variables controlling optional shell behavior.
With no options, or with the -p option, a list of all settable
options is displayed, with an indication of whether or not each is set.
The -p option causes output to be displayed in a form that
may be reused as input.
Other options have the following meanings:
-s- Enable (set) each optname.
-u- Disable (unset) each optname.
-q- Suppresses normal output; the return status
indicates whether the optname is set or unset.
If multiple optname arguments are given with -q,
the return status is zero if all optnames are enabled;
non-zero otherwise.
-o- Restricts the values of
optname to be those defined for the -o option to the
set builtin (see The Set Builtin).
If either -s or -u
is used with no optname arguments, the display is limited to
those options which are set or unset, respectively.
Unless otherwise noted, the shopt options are disabled (off)
by default.
The return status when listing options is zero if all optnames
are enabled, non-zero otherwise. When setting or unsetting options,
the return status is zero unless an optname is not a valid shell
option.
The list of shopt options is:
autocd- If set, a command name that is the name of a directory is executed as if
it were the argument to the
cd command.
This option is only used by interactive shells.
cdable_vars- If this is set, an argument to the
cd builtin command that
is not a directory is assumed to be the name of a variable whose
value is the directory to change to.
cdspell- 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 a character too many.
If a correction is found, the corrected path is printed,
and the command proceeds.
This option is only used by interactive shells.
checkhash- If this is 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- 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 (see Job Control).
The shell always postpones exiting if any jobs are stopped.
checkwinsize- If set, Bash checks the window size after each command
and, if necessary, updates the values of
LINES and COLUMNS.
cmdhist- 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- If set, Bash
changes its behavior to that of version 3.1 with respect to quoted
arguments to the conditional command's =~ operator.
dirspell- If set, Bash
attempts spelling correction on directory names during word completion
if the directory name initially supplied does not exist.
dotglob- If set, Bash includes filenames beginning with a `.' in
the results of filename expansion.
execfail- If this is 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- If set, aliases are expanded as described below under Aliases,
Aliases.
This option is enabled by default for interactive shells.
extdebug- If set, behavior intended for use by debuggers is enabled:
- The -F option to the
declare builtin (see Bash Builtins)
displays the source file name and line number corresponding to each function
name supplied as an argument.
- If the command run by the
DEBUG trap returns a non-zero value, the
next command is skipped and not executed.
- If the command run by the
DEBUG trap returns a value of 2, and the
shell is executing in a subroutine (a shell function or a shell script
executed by the . or source builtins), a call to
return is simulated.
BASH_ARGC and BASH_ARGV are updated as described in their
descriptions (see Bash Variables).
- Function tracing is enabled: command substitution, shell functions, and
subshells invoked with
( command ) inherit the
DEBUG and RETURN traps.
- Error tracing is enabled: command substitution, shell functions, and
subshells invoked with
( command ) inherit the
ERROR trap.
extglob- If set, the extended pattern matching features described above
(see Pattern Matching) are enabled.
extquote- If set,
$'string' and $"string" quoting is
performed within ${parameter} expansions
enclosed in double quotes. This option is enabled by default.
failglob- If set, patterns which fail to match filenames during filename expansion
result in an expansion error.
force_fignore- If set, the suffixes specified by the FIGNORE shell variable
cause words to be ignored when performing word completion even if
the ignored words are the only possible completions.
See Bash Variables, for a description of FIGNORE.
This option is enabled by default.
globstar- If set, the pattern ‘**’ used in a filename expansion context will
match a files and zero or more directories and subdirectories.
If the pattern is followed by a ‘/’, only directories and
subdirectories match.
gnu_errfmt- If set, shell error messages are written in the standard gnu error
message format.
histappend- If set, the history list is appended to the file named by the value
of the HISTFILE
variable when the shell exits, rather than overwriting the file.
histreedit- If set, and Readline
is being used, a user is given the opportunity to re-edit a
failed history substitution.
histverify- If set, and Readline
is being used, the results of history substitution are not immediately
passed to the shell parser. Instead, the resulting line is loaded into
the Readline editing buffer, allowing further modification.
hostcomplete- If set, and Readline is being used, Bash will attempt to perform
hostname completion when a word containing a ‘@’ is being
completed (see Commands For Completion). This option is enabled
by default.
huponexit- If set, Bash will send
SIGHUP to all jobs when an interactive
login shell exits (see Signals).
interactive_comments- Allow a word beginning with ‘#’
to cause that word and all remaining characters on that
line to be ignored in an interactive shell.
This option is enabled by default.
lithist- If enabled, and the
cmdhist
option is enabled, multi-line commands are saved to the history with
embedded newlines rather than using semicolon separators where possible.
login_shell- The shell sets this option if it is started as a login shell
(see Invoking Bash).
The value may not be changed.
mailwarn- 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- 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- If set, Bash matches filenames in a case-insensitive fashion when
performing filename expansion.
nocasematch- If set, Bash matches patterns in a case-insensitive fashion when
performing matching while executing
case or [[
conditional commands.
nullglob- If set, Bash allows filename patterns which match no
files to expand to a null string, rather than themselves.
progcomp- If set, the programmable completion facilities
(see Programmable Completion) are enabled.
This option is enabled by default.
promptvars- If set, prompt strings undergo
parameter expansion, command substitution, arithmetic
expansion, and quote removal after being expanded
as described below (see Printing a Prompt).
This option is enabled by default.
restricted_shell- The shell sets this option if it is started in restricted mode
(see The Restricted Shell).
The value may not be changed.
This is not reset when the startup files are executed, allowing
the startup files to discover whether or not a shell is restricted.
shift_verbose- If this is set, the
shift
builtin prints an error message when the shift count exceeds the
number of positional parameters.
sourcepath- If set, the
source builtin uses the value of PATH
to find the directory containing the file supplied as an argument.
This option is enabled by default.
xpg_echo- If set, the
echo builtin expands backslash-escape sequences
by default.
The return status when listing options is zero if all optnames
are enabled, non-zero otherwise.
When setting or unsetting options, the return status is zero unless an
optname is not a valid shell option.