runuser --help
用法：runuser [选项]... [-] [用户 [参数]... ]
Change the effective user id and group id to that of USER.  Only session PAM
hooks are run, and there is no password prompt.  This command is useful only
when run as the root user.  If run as a non-root user without privilege
to set user ID, the command will fail as the binary is not setuid.
As runuser doesn‘t run auth and account PAM hooks, it runs with lower overhead
than su.

  -, -l, --login               make the shell a login shell, uses runuser-l
                               PAM file instead of default one
  -g --group=group             specify the primary group
  -G --supp-group=group        specify a supplemental group
  -c, --command=COMMAND        pass a single COMMAND to the shell with -c
  --session-command=COMMAND    pass a single COMMAND to the shell with -c
                               and do not create a new session
  -f, --fast                   pass -f to the shell (for csh or tcsh)
  -m, --preserve-environment   do not reset environment variables
  -p                           same as -m
  -s, --shell=SHELL            run SHELL if /etc/shells allows it
      --help        显示此帮助信息并退出
      --version        显示版本信息并退出

单独的"-"选项隐含了-l。如果不指定用户，则假设其为root。

请向bug-coreutils@gnu.org 报告runuser 的错误
GNU coreutils 项目主页：<http://www.gnu.org/software/coreutils/>
GNU 软件一般性帮助：<http://www.gnu.org/gethelp/>
请向<http://translationproject.org/team/zh_CN.html> 报告runuser 的翻译错误
要获取完整文档，请运行：info coreutils ‘runuser invocation‘

# For SELinux we need to use ‘runuser‘ not ‘su‘
if [ -x "/sbin/runuser" ]; then
    SU="/sbin/runuser -s /bin/sh"
else
    SU="/bin/su -s /bin/sh"
fi