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
       configuration.   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 interactive 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.

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  terminal  injection  and  another  security  attacks against
              terminal file descriptors. The all session is also possible to move  to  background
              (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 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  environment  variables  specified in comma separated list when clears
              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.

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/⟩.