Linux常用命令系列——线上查询及帮助命令(help)
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2022-08-04 12:30:19
文章目录: 1.语法 2.选项 3.参数 4.实例 4.1 获取内置命令帮助信息 4.2 获取外置命令帮助信息 1.语法 2.选项 3.参数 4.实例 4.1 获取内置命令帮助信息 4.2 获取外置命令帮助信息 help命令 help命令用于显示shell内部命令的帮助信息。 1.语法 help [ ......
文章目录:
help命令
help命令用于显示shell内部命令的帮助信息。
1.语法
help [选项] [参数]
2.选项
-
- -s:输出短格式的帮助信息。仅包括命令格式。
3.参数
-
- 内部命令:指定需要显示帮助信息的shell内部命令。
4.实例
4.1 获取内置命令帮助信息
[root@localhost ~]# help cd cd: cd [-L|-P] [dir] Change the shell working directory. Change the current directory to DIR. The default DIR is the value of the HOME shell variable. The variable CDPATH defines the search path for the directory containing DIR. Alternative directory names in CDPATH are separated by a colon (:). A null directory name is the same as the current directory. If DIR begins with a slash (/), then CDPATH is not used. If the directory is not found, and the shell option `cdable_vars' is set, the word is assumed to be a variable name. If that variable has a value, its value is used for DIR. Options: -L force symbolic links to be followed -P use the physical directory structure without following symbolic links The default is to follow symbolic links, as if `-L' were specified. Exit Status: Returns 0 if the directory is changed; non-zero otherwise.
4.2 获取外置命令帮助信息
[root@localhost ~]# mv --help Usage: mv [OPTION]... [-T] SOURCE DEST or: mv [OPTION]... SOURCE... DIRECTORY or: mv [OPTION]... -t DIRECTORY SOURCE... Rename SOURCE to DEST, or move SOURCE(s) to DIRECTORY. Mandatory arguments to long options are mandatory for short options too. --backup[=CONTROL] make a backup of each existing destination file -b like --backup but does not accept an argument -f, --force do not prompt before overwriting -i, --interactive prompt before overwrite -n, --no-clobber do not overwrite an existing file If you specify more than one of -i, -f, -n, only the final one takes effect. --strip-trailing-slashes remove any trailing slashes from each SOURCE argument -S, --suffix=SUFFIX override the usual backup suffix -t, --target-directory=DIRECTORY move all SOURCE arguments into DIRECTORY -T, --no-target-directory treat DEST as a normal file -u, --update move only when the SOURCE file is newer than the destination file or when the destination file is missing -v, --verbose explain what is being done --help display this help and exit --version output version information and exit The backup suffix is `~', unless set with --suffix or SIMPLE_BACKUP_SUFFIX. The version control method may be selected via the --backup option or through the VERSION_CONTROL environment variable. Here are the values: none, off never make backups (even if --backup is given) numbered, t make numbered backups existing, nil numbered if numbered backups exist, simple otherwise simple, never always make simple backups Report mv bugs to bug-coreutils@gnu.org GNU coreutils home page: <http://www.gnu.org/software/coreutils/> General help using GNU software: <http://www.gnu.org/gethelp/> For complete documentation, run: info coreutils 'mv invocation'