help 명령어

리눅스 명령어에 대한 사용법을 알려주는 명령어이다.

[root@localhost ~]# help
GNU bash, version 4.1.2(1)-release (x86_64-redhat-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 history -anrw [filename] or hist>
 (( expression ))                                                    if COMMANDS; then COMMANDS; [ elif COMMANDS; then COMMANDS; ]...>
 . filename [arguments]                                              jobs [-lnprs] [jobspec ...] or jobs -x command [args]
 :                                                                   kill [-s sigspec | -n signum | -sigspec] pid | jobspec ... or ki>
 [ arg... ]                                                          let arg [arg ...]
 [[ expression ]]                                                    local [option] name[=value] ...
 alias [-p] [name[=value] ... ]                                      logout [n]
 bg [job_spec ...]                                                   mapfile [-n count] [-O origin] [-s count] [-t] [-u fd] [-C callb>
 bind [-lpvsPVS] [-m keymap] [-f filename] [-q name] [-u name] [-r>  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 ncha>
 cd [-L|-P] [dir]                                                    readarray [-n count] [-O origin] [-s count] [-t] [-u fd] [-C cal>
 command [-pVv] command [arg ...]                                    readonly [-af] [name[=value] ...] or readonly -p
 compgen [-abcdefgjksuv] [-o option]  [-A action] [-G globpat] [-W>  return [n]
 complete [-abcdefgjksuv] [-pr] [-DE] [-o option] [-A action] [-G >  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 [-aAfFilrtux] [-p] [name[=value] ...]                       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] [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] ...] or export -p                        typeset [-aAfFilrtux] [-p] name[=value] ...
 false                                                               ulimit [-SHacdefilmnpqrstuvx] [limit]
 fc [-e ename] [-lnr] [first] [last] or 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] [name ...]
 for (( exp1; exp2; exp3 )); do COMMANDS; done                       until COMMANDS; do COMMANDS; done
 function name { COMMANDS ; } or name () { COMMANDS ; }              variables - Names and meanings of some shell variables
 getopts optstring name [arg]                                        wait [id]
 hash [-lr] [-p pathname] [-dt] [name ...]                           while COMMANDS; do COMMANDS; done
 help [-dms] [pattern ...]                                           { COMMANDS ; }
[root@localhost ~]#

 

[root@localhost ~]# help pwd
pwd: pwd [-LP]
    Print the name of the current working directory.
    
    Options:
      -L	print the value of $PWD if it names the current working
    	directory
      -P	print the physical directory, without any symbolic links
    
    By default, `pwd' behaves as if `-L' were specified.
    
    Exit Status:
    Returns 0 unless an invalid option is given or the current directory
    cannot be read.
[root@localhost ~]#