shopt: shopt [-pqsu] [-o] [选项名 ...]
设定和取消设定 shell 选项。
改变每个 shell 选项 OPTNAME的设定。不带参数
时，列出所有 shell 选项并标注每一个选项是否被
设定。
选项：
-o 限制 OPTNAME 为定义用于`set -o' 的选项
-p 打印每个 shell 选项并标注它的状态。
-q 抑制输出
-s 启用(设定)每个 OPTNAME 选项
-u 禁用(取消设定)每个 OPTNAME 选项
退出状态：
如果 OPTNAME 选项被启用则返回成功；如果是
无效的选项或OPTNAME 被禁用则失败。
shopt命令用于显示和设置shell中的行为选项，通过这些选项以增强shell易用性。shopt命令若不带任何参数选项，则可以显示所有可以设置的shell操作选项。
一些选项的解释bash的man文档即可找到：
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 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 one
character too many. If a correction is found, the corrected filename is printed, and the command proceeds. This option is only used by interactive shells.
checkhash
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
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 above). 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 and locale-specific string comparison when
using the [[ conditional command's < and > operators. Bash versions prior to bash-4.1 use ASCII collation and strcmp(3); bash-4.1 and later use the current locale's collation
sequence and strcoll(3).
compat32
If set, bash changes its behavior to that of version 3.2 with respect to locale-specific string comparison when using the [[ conditional command's < and > operators (see previous
item).
compat40
If set, bash changes its behavior to that of version 4.0 with respect to locale-specific string comparison when using the [[ conditional command's < and > operators (see description
of compat31) and the effect of interrupting a command list. Bash versions 4.0 and later interrupt the list as if the shell received the interrupt; previous versions continue with
the next command in the list.
compat41
If set, bash, when in posix mode, treats a single quote in a double-quoted parameter expansion as a special character. The single quotes must match (an even number) and the charac‐
ters between the single quotes are considered quoted. This is the behavior of posix mode through version 4.1. The default bash behavior remains as in previous versions.
compat42
If set, bash does not process the replacement string in the pattern substitution word expansion using quote removal.
complete_fullquote
If set, bash quotes all shell metacharacters in filenames and directory names when performing completion. If not set, bash removes metacharacters such as the dollar sign from the
set of characters that will be quoted in completed filenames when these metacharacters appear in shell variable references in words to be completed. This means that dollar signs in
variable names that expand to directories will not be quoted; however, any dollar signs appearing in filenames will not be quoted, either. This is active only when bash is using
backslashes to quote completed filenames. This variable is set by default, which is the default bash behavior in versions through 4.2.
direxpand
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
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 pathname expansion.
execfail
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
If set, aliases are expanded as described above under ALIASES. This option is enabled by default for interactive shells.
extdebug
If set, behavior intended for use by debuggers is enabled:
1. The -F option to the declare builtin displays the source file name and line number corresponding to each function name supplied as an argument.
2. If the command run by the DEBUG trap returns a non-zero value, the next command is skipped and not executed.
3. 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.
4. BASH_ARGC and BASH_ARGV are updated as described in their descriptions above.
5. Function tracing is enabled: command substitution, shell functions, and subshells invoked with ( command ) inherit the DEBUG and RETURN traps.
6. Error tracing is enabled: command substitution, shell functions, and subshells invoked with ( command ) inherit the ERR trap.
extglob If set, the extended pattern matching features described above under Pathname Expansion 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 pathname 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 SHELL VARIABLES above for a description of FIGNORE. This option is enabled by default.
globasciiranges
If set, range expressions used in pattern matching bracket expressions (see Pattern Matching above) 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
If set, the pattern ** used in a pathname expansion context will match all files and zero or more directories and subdirectories. If the pattern is followed by a /, only directo‐
ries 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 Completing under READLINE above). This is
enabled by default.
huponexit
If set, bash will send SIGHUP to all jobs when an interactive login shell exits.
interactive_comments
If set, allow a word beginning with # to cause that word and all remaining characters on that line to be ignored in an interactive shell (see COMMENTS above). This option is
enabled by default.
lastpipe
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 If set, 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 INVOCATION above). 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 pathname expansion (see Pathname Expansion above).
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 patterns which match no files (see Pathname Expansion above) to expand to a null string, rather than themselves.
progcomp
If set, the programmable completion facilities (see Programmable Completion above) 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 in PROMPTING above. This option
is enabled by default.
restricted_shell
The shell sets this option if it is started in restricted mode (see RESTRICTED SHELL below). 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 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.
太长了，懒得打中文了