文章目錄： 1.語法 2.選項 3.參數 4.實例 4.1 獲取內置命令幫助信息 4.2 獲取外置命令幫助信息 1.語法 2.選項 3.參數 4.實例 4.1 獲取內置命令幫助信息 4.2 獲取外置命令幫助信息 help命令 help命令用於顯示shell內部命令的幫助信息。 1.語法 help [ ...
文章目錄：
help命令
help命令用於顯示shell內部命令的幫助信息。
1.語法
help [選項] [參數]
2.選項
-
- -s：輸出短格式的幫助信息。僅包括命令格式。
3.參數
-
- 內部命令：指定需要顯示幫助信息的shell內部命令。
4.實例
4.1 獲取內置命令幫助信息
[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 獲取外置命令幫助信息
[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-[email protected]
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'
