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 allows to run commands with a substitute user and group ID. If
the option -u is not given, it 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 configura-
tion. The command runuser does not have to be installed with set-user-
ID permissions.
If the PAM session is not required then recommended solution is to use
setpriv(1) command.
When called without arguments, runuser defaults to running an interac-
tive shell as root.
For backward compatibility, runuser defaults to not change the current
directory and to only set 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 final
environment modification. The command line options like --login or
--preserve-environment affect environment before it's modified by PAM.
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 supplemental 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 unspecified.
-, -l, --login
Start the shell as a login shell with an environment similar to
a real login:
o clears all the environment variables except for TERM
and variables specified by --whitelist-environment
o initializes the environment variables HOME, SHELL,
USER, LOGNAME, PATH
o changes to the target user's home directory
o sets argv[0] of the shell to '-' in order to make the
shell a login shell
-P, --pty
Create pseudo-terminal for the session. The independent terminal
provides better security as user does not share terminal with
the original session. This allow to avoid TIOCSTI ioctl termi-
nal injection and another security attacks against terminal file
descriptors. The all session is also possible to move to back-
ground (e.g., "runuser --pty -u username -- command &"). If the
pseudo-terminal is enabled then runuser command works as a proxy
between the sessions (copy stdin and stdout).
This feature is mostly designed for interactive sessions. If the
standard input is not a terminal, but for example pipe (e.g.,
echo "date" | runuser --pty -u user) than ECHO flag for the
pseudo-terminal is disabled to avoid messy output.
-m, -p, --preserve-environment
Preserve the entire environment, i.e., it does not set HOME,
SHELL, USER nor 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:
o the shell specified with --shell
o the shell specified in the environment variable SHELL
if the --preserve-environment option is used
o the shell listed in the passwd entry of the target
user
o /bin/sh
If the target user has a restricted shell (i.e., not listed in
/etc/shells) the --shell option and the SHELL environment vari-
ables 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 environment variables specified in comma separated
list when clears environment for --login. The whitelist is ig-
nored for the environment variables HOME, SHELL, USER, LOGNAME,
and PATH.
-V, --version
Display version information and exit.
-h, --help
Display help text and exit.
CONFIG FILES
runuser reads the /etc/default/runuser and /etc/login.defs configura-
tion files. The following configuration items are relevant for
runuser:
ENV_PATH (string)
Defines the PATH environment variable for a regular user. The de-
fault 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 spec-
ified 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 --lo-
gin command line option and PAM system setting (e.g. pam_env).
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
SEE ALSO
setpriv(1), su(1), login.defs(5), shells(5), pam(8)
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.
AVAILABILITY
The runuser command is part of the util-linux package and is available
from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-
linux/>.
util-linux July 2014 RUNUSER(1)