RUNUSER(1) User Commands RUNUSER(1)
NAME
runuser - run a command with substitute user and group ID
SYNOPSIS
runuser [options] -u user [[--] command [argument...]]
runuser [options] [-] [user [argument...]]
DESCRIPTION
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.
OPTIONS
-c, --command=command
Pass command to the shell with the -c option.
-f, --fast
Pass -f to the shell, which may or may not be useful, depending on
the shell.
-g, --group=group
The primary group to be used. This option is allowed for the root
user only.
-G, --supp-group=group
Specify a supplementary group. This option is available to the root
user only. The first specified supplementary group is also used as
a primary group if the option --group is not specified.
-, -l, --login
Start the shell as a login shell with an environment similar to a
real login:
• clears all the environment variables except for TERM and
variables specified by --whitelist-environment
• initializes the environment variables HOME, SHELL, USER,
LOGNAME, and PATH
• changes to the target user’s home directory
• sets argv[0] of the shell to '-' in order to make the shell a
login shell
-P, --pty
Create a pseudo-terminal for the session. The independent terminal
provides better security as the user does not share a terminal with
the original session. This can be used to avoid TIOCSTI ioctl
terminal injection and other security attacks against terminal file
descriptors. The entire session can also be moved to the background
(e.g., runuser --pty -u username -- command &). If the
pseudo-terminal is enabled, then runuser works as a proxy between
the sessions (sync stdin and stdout).
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
Preserve the entire environment, i.e., do not set HOME, SHELL, USER
or LOGNAME. The option is ignored if the option --login is
specified.
-s, --shell=shell
Run the specified shell instead of the default. The shell to run is
selected according to the following rules, in order:
• the shell specified with --shell
• the shell specified in the environment variable SHELL if the
--preserve-environment option is used
• the shell listed in the passwd entry of the target user
• /bin/sh
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.
--session-command=command
Same as -c, but do not create a new session. (Discouraged.)
-w, --whitelist-environment=list
Don’t reset the environment variables specified in the
comma-separated list when clearing the environment for --login. The
whitelist is ignored for the environment variables HOME, SHELL,
USER, LOGNAME, and PATH.
-h, --help
Display help text and exit.
-V, --version
Print version and exit.
CONFIG FILES
runuser reads the /etc/default/runuser and /etc/login.defs
configuration files. The following configuration items are relevant for
runuser:
ENV_PATH (string)
Defines the PATH environment variable for a regular user. The
default value is /usr/local/bin:/bin:/usr/bin.
ENV_ROOTPATH (string), ENV_SUPATH (string)
Defines the PATH environment variable for root. ENV_SUPATH takes
precedence. The default value is
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin.
ALWAYS_SET_PATH (boolean)
If set to yes and --login and --preserve-environment were not
specified runuser initializes PATH.
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)).
EXIT STATUS
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:
1
Generic error before executing the requested command
126
The requested command could not be executed
127
The requested command was not found
FILES
/etc/pam.d/runuser
default PAM configuration file
/etc/pam.d/runuser-l
PAM configuration file if --login is specified
/etc/default/runuser
runuser specific logindef config file
/etc/login.defs
global logindef config file
HISTORY
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.
SEE ALSO
setpriv(1), su(1), login.defs(5), shells(5), pam(8)
REPORTING BUGS
For bug reports, use the issue tracker at
https://github.com/util-linux/util-linux/issues.
AVAILABILITY
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/>.
util-linux 2.38.1 2022-05-11 RUNUSER(1)
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