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171 lines
5.9 KiB
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171 lines
5.9 KiB
Markdown
Linux / Unix Bash Shell List All Builtin Commands
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======
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Builtin commands contained within the bash shell itself. How do I list all built-in bash commands on Linux / Apple OS X / *BSD / Unix like operating systems without reading large size bash man page?
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A shell builtin is nothing but command or a function, called from a shell, that is executed directly in the shell itself. The bash shell executes the command directly, without invoking another program. You can view information for Bash built-ins with help command. There are different types of built-in commands.
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### built-in command types
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1. Bourne Shell Builtins: Builtin commands inherited from the Bourne Shell.
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2. Bash Builtins: Table of builtins specific to Bash.
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3. Modifying Shell Behavior: Builtins to modify shell attributes and optional behavior.
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4. Special Builtins: Builtin commands classified specially by POSIX.
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### How to see all bash builtins
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Type the following command:
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```
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$ help
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$ help | less
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$ help | grep read
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```
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Sample outputs:
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```
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GNU bash, version 4.1.5(1)-release (x86_64-pc-linux-gnu)
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These shell commands are defined internally. Type `help' to see this list.
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Type `help name' to find out more about the function `name'.
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Use `info bash' to find out more about the shell in general.
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Use `man -k' or `info' to find out more about commands not in this list.
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A star (*) next to a name means that the command is disabled.
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job_spec [&] history [-c] [-d offset] [n] or hist>
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(( expression )) if COMMANDS; then COMMANDS; [ elif C>
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. filename [arguments] jobs [-lnprs] [jobspec ...] or jobs >
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: kill [-s sigspec | -n signum | -sigs>
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[ arg... ] let arg [arg ...]
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[[ expression ]] local [option] name[=value] ...
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alias [-p] [name[=value] ... ] logout [n]
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bg [job_spec ...] mapfile [-n count] [-O origin] [-s c>
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bind [-lpvsPVS] [-m keymap] [-f filen> popd [-n] [+N | -N]
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break [n] printf [-v var] format [arguments]
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builtin [shell-builtin [arg ...]] pushd [-n] [+N | -N | dir]
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caller [expr] pwd [-LP]
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case WORD in [PATTERN [| PATTERN]...)> read [-ers] [-a array] [-d delim] [->
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cd [-L|-P] [dir] readarray [-n count] [-O origin] [-s>
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command [-pVv] command [arg ...] readonly [-af] [name[=value] ...] or>
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compgen [-abcdefgjksuv] [-o option] > return [n]
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complete [-abcdefgjksuv] [-pr] [-DE] > select NAME [in WORDS ... ;] do COMM>
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compopt [-o|+o option] [-DE] [name ..> set [--abefhkmnptuvxBCHP] [-o option>
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continue [n] shift [n]
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coproc [NAME] command [redirections] shopt [-pqsu] [-o] [optname ...]
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declare [-aAfFilrtux] [-p] [name[=val> source filename [arguments]
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dirs [-clpv] [+N] [-N] suspend [-f]
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disown [-h] [-ar] [jobspec ...] test [expr]
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echo [-neE] [arg ...] time [-p] pipeline
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enable [-a] [-dnps] [-f filename] [na> times
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eval [arg ...] trap [-lp] [[arg] signal_spec ...]
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exec [-cl] [-a name] [command [argume> true
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exit [n] type [-afptP] name [name ...]
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export [-fn] [name[=value] ...] or ex> typeset [-aAfFilrtux] [-p] name[=val>
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false ulimit [-SHacdefilmnpqrstuvx] [limit>
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fc [-e ename] [-lnr] [first] [last] o> umask [-p] [-S] [mode]
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fg [job_spec] unalias [-a] name [name ...]
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for NAME [in WORDS ... ] ; do COMMAND> unset [-f] [-v] [name ...]
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for (( exp1; exp2; exp3 )); do COMMAN> until COMMANDS; do COMMANDS; done
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function name { COMMANDS ; } or name > variables - Names and meanings of so>
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getopts optstring name [arg] wait [id]
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hash [-lr] [-p pathname] [-dt] [name > while COMMANDS; do COMMANDS; done
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help [-dms] [pattern ...] { COMMANDS ; }
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```
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### Viewing information for Bash built-ins
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To get detailed info run:
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```
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help command
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help read
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```
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To just get a list of all built-ins with a short description, execute:
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`$ help -d`
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### Find syntax and other options for builtins
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Use the following syntax ' to find out more about the builtins commands:
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```
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help name
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help cd
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help fg
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help for
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help read
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help :
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```
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Sample outputs:
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```
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:: :
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Null command.
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No effect; the command does nothing.
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Exit Status:
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Always succeeds
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```
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### Find out if a command is internal (builtin) or external
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Use the type command or command command:
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```
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type -a command-name-here
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type -a cd
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type -a uname
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type -a :
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type -a ls
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```
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OR
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```
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type -a cd uname : ls uname
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```
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Sample outputs:
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```
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cd is a shell builtin
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uname is /bin/uname
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: is a shell builtin
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ls is aliased to `ls --color=auto'
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ls is /bin/ls
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l is a function
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l ()
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{
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ls --color=auto
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}
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```
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OR
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```
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command -V ls
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command -V cd
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command -V foo
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```
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[![View list bash built-ins command info on Linux or Unix][1]][1]
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### about the author
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The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on [Twitter][2], [Facebook][3], [Google+][4].
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--------------------------------------------------------------------------------
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via: https://www.cyberciti.biz/faq/linux-unix-bash-shell-list-all-builtin-commands/
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作者:[Vivek Gite][a]
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译者:[译者ID](https://github.com/译者ID)
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校对:[校对者ID](https://github.com/校对者ID)
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本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译,[Linux中国](https://linux.cn/) 荣誉推出
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[a]:https://www.cyberciti.biz
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[1]:https://www.cyberciti.biz/media/new/faq/2013/03/View-list-bash-built-ins-command-info-on-Linux-or-Unix.jpg
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[2]:https://twitter.com/nixcraft
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[3]:https://facebook.com/nixcraft
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[4]:https://plus.google.com/+CybercitiBiz
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