SU

su(super user)

中文解释：su(super user)
功能说明：变更用户身份。
语　　法：su [-flmp][--help][--version][-][-c <指令>][-s <shell>][用户帐号]
补充说明：su可让用户暂时变更登入的身份。变更时须输入所要变更的用户帐号与密码。
参　　数：
　-c<指令>或--command=<指令> 　执行完指定的指令后，即恢复原来的身份。 
　-f或--fast 　适用于csh与tsch，使shell不用去读取启动文件。 
　-.-l或--login 　改变身份时，也同时变更工作目录，以及HOME,SHELL,USER,LOGNAME。此外，也会变更PATH变量。  
　-m,-p或--preserve-environment 　变更身份时，不要变更环境变量。 
　-s<shell>或--shell=<shell> 　指定要执行的shell。 
　--help 　显示帮助。 
　--version 　显示版本信息。 
　[用户帐号] 　指定要变更的用户。若不指定此参数，则预设变更为root

英文解释：

su

su [option] [user] [shell_args]

Create a shell with the effective user ID user. If no user is specified, create a shell for a privileged user (i.e., become a superuser). Enter EOF to terminate. You can run the shell with particular options by passing them as shell_args (e.g., if the shell runs bash, you can specify -c command to execute command via bash, or -r to create a restricted shell).

Options

-, -l, --login

Go through the entire login sequence (i.e., change to user's environment).

-c command, --command=command

Execute command in the new shell and then exit immediately. If command is more than one word, it should be enclosed in quotes. For example:

su -c 'find / -name *.c -print' nobody

-f, --fast

Start the shell with the -f option, which suppresses the reading of the .cshrc or .tcshrc file. Applies to csh and tcsh.

-m, -p, --preserve-environment

Do not reset environment variables.

-s shell, --shell=shell

Execute shell, not the shell specified in /etc/passwd, unless shell is restricted.

--help

Print a help message and then exit.

--version

Print version information and then exit.

Examples

Become root and obtain all of root's user environment:

&dollar; su -

Become root long enough to restart the Apache httpd web server, then revert to the current user:

&dollar; su -c /etc/rc.d/init.d/httpd restart

sliplogin(上) sudo(下)