runuser - run a command with substitute user and group ID
runuser [options] -u user [[--] command [argument...]]
runuser [options] [-] [user [argument...]]
runuser can be used to run commands with a substitute user and group ID. If the option -u is not given, runuser falls back to su-compatible semantics and a shell is executed. The difference between the commands runuser and su is that runuser does not ask for a password (because it may be executed by the root user only) and it uses a different PAM configuration. The command runuser does not have to be installed with set-user-ID permissions.
If the PAM session is not required, then the recommended solution is to use the setpriv(1) command.
When called without arguments, runuser defaults to running an interactive shell as root.
For backward compatibility, runuser defaults to not changing the current directory and to setting only the environment variables HOME and SHELL (plus USER and LOGNAME if the target user is not root). This version of runuser uses PAM for session management.
Note that runuser in all cases use PAM (pam_getenvlist()) to do the final environment modification. Command-line options such as --login and --preserve-environment affect the environment before it is modified by PAM.
Since version 2.38 runuser resets process resource limits RLIMIT_NICE, RLIMIT_RTPRIO, RLIMIT_FSIZE, RLIMIT_AS and RLIMIT_NOFILE.
-, -l, --login
This feature is mostly designed for interactive sessions. If the standard input is not a terminal, but for example a pipe (e.g., echo "date" | runuser --pty -u user), then the ECHO flag for the pseudo-terminal is disabled to avoid messy output.
-m, -p, --preserve-environment
If the target user has a restricted shell (i.e., not listed in /etc/shells), then the --shell option and the SHELL environment variables are ignored unless the calling user is root.
runuser reads the /etc/default/runuser and /etc/login.defs configuration files. The following configuration items are relevant for runuser:
ENV_ROOTPATH (string), ENV_SUPATH (string)
The environment variable PATH may be different on systems where /bin and /sbin are merged into /usr; this variable is also affected by the --login command-line option and the PAM system setting (e.g., pam_env(8)).
runuser normally returns the exit status of the command it executed. If the command was killed by a signal, runuser returns the number of the signal plus 128.
Exit status generated by runuser itself:
This runuser command was derived from coreutils' su, which was based on an implementation by David MacKenzie, and the Fedora runuser command by Dan Walsh.
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.
The runuser command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.