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 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.

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.

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)