shell命令--help
shell命令--help
0、help命令的专属图床
点此快速打开文章【图床_shell命令help】
1、help命令的功能说明
在
Linux
系统里有一些特殊的命令 ,它们就是bash
程序的内置命令 ,例如cd
、history
、read
等 ,这些命令在系统目录里不存在真实的程序文件(存在于bash
程序里 ),对于这部分命令,查看帮助的方法就是使用help
命令。
2、help命令的语法格式
help: help [-dms] [pattern ...] Display information about builtin commands. Displays brief summaries of builtin commands. If PATTERN is specified, gives detailed help on all commands matching PATTERN, otherwise the list of help topics is printed. Options: -d output short description for each topic -m display usage in pseudo-manpage format -s output only a short usage synopsis for each topic matching PATTERN Arguments: PATTERN Pattern specifiying a help topic Exit Status: Returns success unless PATTERN is not found or an invalid option is given.
3、help命令的选项说明
help
选项不常用,此处省略。
4、help命令的实践操作
范例1:使用
help
查看cd
命令help cd
范例2:使用
man
查看cd
命令man cd
内置命令也有很多,如下:
NAME bash, :, ., [, alias, bg, bind, break, builtin, caller, cd, command, compgen, complete, compopt, continue, declare, dirs, disown, echo, enable, eval, exec, exit, export, false, fc, fg, getopts, hash, help, history, jobs, kill, let, local, logout, mapfile, popd, printf, pushd, pwd, read, readonly, return, set, shift, shopt, source, suspend, test, times, trap, true, type, typeset, ulimit, umask, unalias, unset, wait - bash built-in commands, see bash(1)
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