列出所有的 Bash Shell 內建指令

shell 內建指令就是一個指令或一個函數，從 shell 中調用，它直接在 shell 中執行。 bash shell 直接執行該指令而無需呼叫其他程式。你可以使用 help 指令來查看 Bash 內建指令的資訊。以下是幾種不同類型的內建指令。

內建指令的類型

#類型如下：
Bourne Shell 內建指令：內建指令繼承自 Bourne Shell。
Bash 內建指令：特定於 Bash 的內建指令表。
修改 Shell 行為：修改 shell 屬性和可選行為的內建指令。
特別的內建指令：由 POSIX 特別分類的內建指令。

如何查看所有 bash 內建指令

有以下的指令：

$ help
$ help | less
$ help | grep read

範例輸出：

GNU bash, version 4.1.5(1)-release (x86_64-pc-linux-gnu)
These shell commands are defined internally.  Type `help' to see this list.
Type `help name' to find out more about the function `name'.
Use `info bash' to find out more about the shell in general.
Use `man -k' or `info' to find out more about commands not in this list.
A star (*) next to a name means that the command is disabled.
 job_spec [&]                            history [-c] [-d offset] [n] or hist>
 (( expression ))                        if COMMANDS; then COMMANDS; [ elif C>
 . filename [arguments]                  jobs [-lnprs] [jobspec ...] or jobs >
 :                                       kill [-s sigspec | -n signum | -sigs>
 [ arg... ]                              let arg [arg ...]
 [[ expression ]]                        local [option] name[=value] ...
 alias [-p] [name[=value] ... ]          logout [n]
 bg [job_spec ...]                       mapfile [-n count] [-O origin] [-s c>
 bind [-lpvsPVS] [-m keymap] [-f filen>  popd [-n] [+N | -N]
 break [n]                               printf [-v var] format [arguments]
 builtin [shell-builtin [arg ...]]       pushd [-n] [+N | -N | dir]
 caller [expr]                           pwd [-LP]
 case WORD in [PATTERN [| PATTERN]...)>  read [-ers] [-a array] [-d delim] [->
 cd [-L|-P] [dir]                        readarray [-n count] [-O origin] [-s>
 command [-pVv] command [arg ...]        readonly [-af] [name[=value] ...] or>
 compgen [-abcdefgjksuv] [-o option]  >  return [n]
 complete [-abcdefgjksuv] [-pr] [-DE] >  select NAME [in WORDS ... ;] do COMM>
 compopt [-o|+o option] [-DE] [name ..>  set [--abefhkmnptuvxBCHP] [-o option>
 continue [n]                            shift [n]
 coproc [NAME] command [redirections]    shopt [-pqsu] [-o] [optname ...]
 declare [-aAfFilrtux] [-p] [name[=val>  source filename [arguments]
 dirs [-clpv] [+N] [-N]                  suspend [-f]
 disown [-h] [-ar] [jobspec ...]         test [expr]
 echo [-neE] [arg ...]                   time [-p] pipeline
 enable [-a] [-dnps] [-f filename] [na>  times
 eval [arg ...]                          trap [-lp] [[arg] signal_spec ...]
 exec [-cl] [-a name] [command [argume>  true
 exit [n]                                type [-afptP] name [name ...]
 export [-fn] [name[=value] ...] or ex>  typeset [-aAfFilrtux] [-p] name[=val>
 false                                   ulimit [-SHacdefilmnpqrstuvx] [limit>
 fc [-e ename] [-lnr] [first] [last] o>  umask [-p] [-S] [mode]
 fg [job_spec]                           unalias [-a] name [name ...]
 for NAME [in WORDS ... ] ; do COMMAND>  unset [-f] [-v] [name ...]
 for (( exp1; exp2; exp3 )); do COMMAN>  until COMMANDS; do COMMANDS; done
 function name { COMMANDS ; } or name >  variables - Names and meanings of so>
 getopts optstring name [arg]            wait [id]
 hash [-lr] [-p pathname] [-dt] [name >  while COMMANDS; do COMMANDS; done
 help [-dms] [pattern ...]               { COMMANDS ; }

另外一種選擇是使用下列指令：

compgen -b
compgen -b | more

查看 Bash 內建的指令資訊

運行以下得到詳細資訊：

help command
help read

要僅得到所有帶有簡短描述的內建指令的列表，執行如下:

$ help -d

尋找內建指令的語法和其他選項

使用下列語法去找出更多相關的內建指令：

help name 
help cd 
help fg 
help for 
help read 
help :

範例輸出：

:: :
 Null command.
 
 No effect; the command does nothing.
 
 Exit Status:
 Always succeeds

找出一個指令是內部的（內建）還是外部的

#使用 type 指令或 command 指令：

type -a command-name-here 
type -a cd 
type -a uname 
type -a : 
type -a ls

或：

type -a cd uname : ls uname

範例輸出：

cd is a shell builtin
uname is /bin/uname
: is a shell builtin
ls is aliased to `ls --color=auto'
ls is /bin/ls
l is a function
l ()
{
 ls --color=auto
}

或：

command -V ls 
command -V cd 
command -V foo

# 作者：Vivek Gite

以上是列出所有的 Bash Shell 內建指令的詳細內容。更多資訊請關注PHP中文網其他相關文章！