linux命令之help
1.help介绍
linux命令help用来显示内置命令的帮助信息
2.help用法
help [参数] command
help参数
参数 说明
-d 输出每个命令的简短描述
-m 以手册页格式显示命令用法
-s 仅输出每个匹配命令的简短使用概要
3.实例
3.1.以手册页格式显示命令用法
命令：
help -m
[root@rhel77 ~]# help -m
GNU bash, version 4.2.46(2)-release (x86_64-redhat-linux-gnu)
These shell commands are defined internally. Type help' to see this list. Typehelp name' to find out more about the function name'. Useinfo bash' to find out more about the shell in general.
Use man -k' orinfo' 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 [file>
(( expression )) if COMMANDS; then COMMANDS; [ elif COMMANDS; then C>
. filename [arguments] jobs [-lnprs] [jobspec ...] or jobs -x command [arg>
: kill [-s sigspec | -n signum | -sigspec] pid | jobs>
[ 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 >
bind [-lpvsPVS] [-m keymap] [-f filename] [-q name] > 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 ;;]..> read [-ers] [-a array] [-d delim] [-i text] [-n nch>
cd [-L|[-P [-e]]] [dir] readarray [-n count] [-O origin] [-s count] [-t] [->
command [-pVv] command [arg ...] readonly [-aAf] [name[=value] ...] or readonly -p
compgen [-abcdefgjksuv] [-o option] [-A action] [-G> return [n]
complete [-abcdefgjksuv] [-pr] [-DE] [-o option] [-A> 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 [-aAfFgilrtux] [-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 ...]] [redi> true
exit [n] type [-afptP] name [name ...]
export [-fn] [name[=value] ...] or export -p typeset [-aAfFgilrtux] [-p] name[=value] ...
false ulimit [-SHacdefilmnpqrstuvx] [limit]
fc [-e ename] [-lnr] [first] [last] or fc -s [pat=re> 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 variab>
getopts optstring name [arg] wait [id]
hash [-lr] [-p pathname] [-dt] [name ...] while COMMANDS; do COMMANDS; done
help [-dms] [pattern ...] { COMMANDS ; }
[root@rhel77 ~]#
3.2.输出内置命令的简短描述
命令：
help -d fg
[root@rhel77 ~]# help -d fg
fg - Move job to the foreground.
[root@rhel77 ~]#
3.3.仅输出内置命令的简短使用概要
命令：
help -s fg
[root@rhel77 ~]# help -s fg
fg: fg [job_spec]
[root@rhel77 ~]#
3.4.显示help命令的用法
命令：
help help
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版权声明：本文为CSDN博主「小黑要上天」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/z19861216/article/details/134454785
