runuser

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.

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:

           o   clears all the environment variables except for TERM and
               variables specified by --whitelist-environment

           o   initializes the environment variables HOME, SHELL, USER,
               LOGNAME, and 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 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:

           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), 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.

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/karelzak/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 2.37.2                 2021-06-02                        RUNUSER(1)