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=commandPass command
to the shell with the −c option.
−f,
−−fastPass −f to the
shell, which may or may not be useful, depending on the
shell.
−g,
−−group=groupThe primary group to be used. This option is allowed for the root user only.
−G,
−−supp−group=groupSpecify 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, −−loginStart the shell as a login shell with an environment similar to a real login:
clears all the environment variables except for
TERMand variables specified by−−whitelist−environmentinitializes the environment variables
HOME,SHELL,USER,LOGNAME, andPATHchanges to the target user's home directory
sets argv[0] of the shell to '
−' in order to make the shell a login shell
−P,
−−ptyCreate 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−environmentPreserve 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=shellRun the specified shell instead of the default. The shell to run is selected according to the following rules, in order:
the shell specified with
−−shellthe shell specified in the environment variable
SHELLif the−−preserve−environmentoption is usedthe 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=commandSame as −c, but do
not create a new session. (Discouraged.)
−w,
−−whitelist−environment=listDon'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,
−−versionDisplay version information and exit.
−h,
−−helpDisplay 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
PATHenvironment variable for root.ENV_SUPATHtakes 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:
1Generic error before executing the requested command
126The requested command could not be executed
127The requested command was not found
/etc/pam.d/runuserdefault PAM configuration file
/etc/pam.d/runuser-lPAM configuration file if −−login is specified
/etc/default/runuserrunuser specific logindef config file
/etc/login.defsglobal 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.
The runuser command is part of the util-linux package and is available from Linux Kernel Archive
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