bash 組み込み関数

<h3>helpコマンドで表示できます。</h3>

```
[root@centos8_1 ~]# help
GNU bash, バージョン 4.4.20(1)-release (x86_64-redhat-linux-gnu)
これらのシェルコマンドは内部で定義されています。`help' と入力して一覧を参照してください。
`help 名前' と入力すると `名前' という関数のより詳しい説明が得られます。
'info bash' を使用するとシェル全般のより詳しい説明が得られます。
`man -k' または info を使用すると一覧にないコマンドのより詳しい説明が得られます。

名前の後にアスタリスク (*) がある場合はそのコマンドが無効になっていることを意味します。

 job_spec [&]                                                                  history [-c] [-d offset] [n] または history -anrw [filename] または histor>
 (( expression ))                                                              if COMMANDS; then COMMANDS; [ elif COMMANDS; then COMMANDS; ]... [ else CO>
 . filename [arguments]                                                        jobs [-lnprs] [jobspec ...] または jobs -x command [args]
 :                                                                             kill [-s sigspec | -n signum | -sigspec] pid | jobspec ... または kill -l >
 [ arg... ]                                                                    let 引数 [引数 ...]
 [[ expression ]]                                                              local [option] name[=value] ...
 alias [-p] [name[=value] ... ]                                                logout [n]
 bg [job_spec ...]                                                             mapfile [-d delim] [-n count] [-O origin] [-s count] [-t] [-u fd] [-C call>
 bind [-lpsvPSVX] [-m keymap] [-f filename] [-q name] [-u name] [-r keyseq] >  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]...) COMMANDS ;;]... esac                    read [-ers] [-a array] [-d delim] [-i text] [-n nchars] [-N nchars] [-p pr>
 cd [-L|[-P [-e]] [-@]] [dir]                                                  readarray [-n count] [-O origin] [-s count] [-t] [-u fd] [-C callback] [-c>
 command [-pVv] command [arg ...]                                              readonly [-aAf] [name[=value] ...] または readonly -p
 compgen [-abcdefgjksuv] [-o option] [-A action] [-G globpat] [-W wordlist] >  return [n]
 complete [-abcdefgjksuv] [-pr] [-DE] [-o option] [-A action] [-G globpat] [>  select NAME [in WORDS ... ;] do COMMANDS; done
 compopt [-o|+o option] [-DE] [name ...]                                       set [-abefhkmnptuvxBCHP] [-o option-name] [--] [arg ...]
 continue [n]                                                                  shift [n]
 coproc [NAME] command [redirections]                                          shopt [-pqsu] [-o] [optname ...]
 declare [-aAfFgilnrtux] [-p] [name[=value] ...]                               source filename [arguments]
 dirs [-clpv] [+N] [-N]                                                        suspend [-f]
 disown [-h] [-ar] [jobspec ... | pid ...]                                     test [expr]
 echo [-neE] [arg ...]                                                         time [-p] pipeline
 enable [-a] [-dnps] [-f filename] [name ...]                                  times
 eval [arg ...]                                                                trap [-lp] [[arg] signal_spec ...]
 exec [-cl] [-a name] [command [arguments ...]] [redirection ...]              true
 exit [n]                                                                      type [-afptP] name [name ...]
 export [-fn] [name[=value] ...] または export -p                              typeset [-aAfFgilnrtux] [-p] name[=value] ...
 false                                                                         ulimit [-SHabcdefiklmnpqrstuvxPT] [limit]
 fc [-e ename] [-lnr] [first] [last] または fc -s [pat=rep] [command]          umask [-p] [-S] [mode]
 fg [job_spec]                                                                 unalias [-a] name [name ...]
 for NAME [in WORDS ... ] ; do COMMANDS; done                                  unset [-f] [-v] [-n] [name ...]
 for (( exp1; exp2; exp3 )); do COMMANDS; done                                 until COMMANDS; do COMMANDS; done
 function name { COMMANDS ; } または name () { COMMANDS ; }                    変数 - 変数の名前とその意味
 getopts optstring name [arg]                                                  wait [-n] [id ...]
 hash [-lr] [-p pathname] [-dt] [name ...]                                     while COMMANDS; do COMMANDS; done
 help [-dms] [pattern ...]                                                     { COMMANDS ; }
[root@centos8_1 ~]#
[root@centos8_1 ~]#
```

<h3>個別ではtype -a で表示できます</h3>

```
[root@centos8_1 ~]# type -a ulimit
ulimit はシェル組み込み関数です
ulimit は /usr/bin/ulimit です
[root@centos8_1 ~]#
```