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.
- -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 (copy 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.
- -V, --version
- Display version information and exit.
- -h, --help
- Display help text 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.