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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | CONFIG FILES | EXIT STATUS | FILES | HISTORY | SEE ALSO | REPORTING BUGS | AVAILABILITY |
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RUNUSER(1) User Commands RUNUSER(1)
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.
-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,
COLORTERM, NO_COLOR 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
-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.
-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 user --
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.
-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.)
-T, --no-pty
Do not create a pseudo-terminal, opposite of --pty and -P.
Note that running without a pseudo-terminal opens the security
risk of privilege escalation through TIOCSTI/TIOCLINUX ioctl
command injection.
-u, --user=user
Run command with the effective user ID and group ID of the
user name user.
-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
Display version and exit.
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)).
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
/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
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.
setpriv(1), su(1), login.defs(5), shells(5), pam(8)
For bug reports, use the issue tracker
<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/>. This page is
part of the util-linux (a random collection of Linux utilities)
project. Information about the project can be found at
⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you have a
bug report for this manual page, send it to
[email protected]. This page was obtained from the
project's upstream Git repository
⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
2025-08-11. (At that time, the date of the most recent commit that
was found in the repository was 2025-08-05.) If you discover any
rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a
mail to [email protected]
util-linux 2.42-start-521-ec46 2025-08-09 RUNUSER(1)
Pages that refer to this page: setpriv(1), su(1), credentials(7)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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