.TH RUNUSER "1" "August 2012" "util-linux" "User Commands"
.SH NAME
runuser \- run a command with substitute user and group ID
.SH SYNOPSIS
.B runuser
[options...] [\-] [user [args...]]
.SH DESCRIPTION
.B runuser
allows to run commands with substitute user and group ID.
The difference between the commands
.B runuser
and
.B su
is that
.B runuser
does not ask for password, because it may be executed by root user only.
The command
.B runuser
does not have to be installed with suid permissions.
.PP
When called without arguments
.B runuser
defaults to running an interactive shell as
.IR root .
.PP
For backward compatibility
.B runuser
defaults to not change the current directory and to only set the
environment variables
.B HOME
and
.B SHELL
(plus
.B USER
and
.B LOGNAME
if the target
.I user
is not root).  It is recommended to always use the
.B \-\-login
option (instead it's shortcut
.BR \- )
to avoid side effects caused by mixing environments.
.PP
This version of
.B runuser
uses PAM for session management.
.SH OPTIONS
.TP
\fB\-c\fR \fIcommand\fR, \fB\-\-command\fR=\fIcommand\fR
Pass
.I command
to the shell with the
.B \-c
option.
.TP
\fB\-\-session\-command\fR=\fIcommand\fR
Same as
.B \-c
but do not create a new session (discouraged).
.TP
\fB\-f\fR, \fB\-\-fast\fR
Pass
.B \-f
to the shell which may or may not be useful depending on the
shell.
.TP
\fB\-g\fR, \fB\-\-group\fR=\fIgroup\fR\fR
specify the primary group, this option is allowed for root user only
.TP
\fB\-G\fR, \fB\-\-supp-group\fR=\fIgroup\fR\fR
specify a supplemental group, this option is allowed for root user only
.TP
\fB\-\fR, \fB\-l\fR, \fB\-\-login\fR
Starts the shell as login shell with an environment similar to a real
login:
.RS 10
.TP
o
clears all environment variables except for
.B TERM
.TP
o
initializes the environment variables
.BR HOME ,
.BR SHELL ,
.BR USER ,
.BR LOGNAME ,
.B PATH
.TP
o
changes to the target user's home directory
.TP
o
sets argv[0] of the shell to
.RB ' \- '
in order to make the shell a login shell
.RE
.TP
\fB\-m\fR, \fB\-p\fR, \fB\-\-preserve-environment\fR
Preserves the whole environment, ie does not set
.BR HOME ,
.BR SHELL ,
.B USER
nor
.BR LOGNAME .
.TP
\fB\-s\fR \fISHELL\fR, \fB\-\-shell\fR=\fISHELL\fR
Runs the specified shell instead of the default.  The shell to run is
selected according to the following rules in order:
.RS 10
.TP
o
the shell specified with
.B \-\-shell
.TP
o
The shell specified in the environment variable
.B SHELL
if the
.B \-\-preserve-environment
option is used.
.TP
o
the shell listed in the passwd entry of the target user
.TP
o
/bin/sh
.RE
.IP
If the target user has a restricted shell (i.e. not listed in
/etc/shells) the
.B \-\-shell
option and the
.B SHELL
environment variables are ignored unless the calling user is root.
.TP
\fB\-\-help\fR
Display help text and exit.
.TP
\fB\-\-version\fR
Display version information and exit.
.SH CONFIG FILES
.B runuser
reads the
.I /etc/default/runuser
and
.I /etc/login.defs
configuration files.  The following configuration items are relevant
for
.BR runuser :
.PP
.B ENV_PATH
(string)
.RS 4
Defines the PATH environment variable for a regular user.  The
default value is
.IR /usr/local/bin:\:/bin:\:/usr/bin .
.RE
.PP
.B ENV_ROOTPATH
(string)
.br
.B ENV_SUPATH
(string)
.RS 4
Defines the PATH environment variable for root. The default value is
.IR /usr/local/sbin:\:/usr/local/bin:\:/sbin:\:/bin:\:/usr/sbin:\:/usr/bin .
.RE
.PP
.B ALWAYS_SET_PATH
(boolean)
.RS 4
If set to
.I yes
and \-\-login and \-\-preserve\-environment were not specified
.B runuser
initializes
.BR PATH .
.RE
.SH EXIT STATUS
.B runuser
normally returns the exit status of the command it executed.  If the
command was killed by a signal,
.B runuser
returns the number of the signal plus 128.
.PP
Exit status generated by
.B runuser
itself:
.RS 10
.TP
1
Generic error before executing the requested command
.TP
126
The requested command could not be executed
.TP
127
The requested command could was not found
.RE
.SH FILES
.PD 0
.TP 17
/etc/pam.d/runuser
default PAM configuration file
.TP
/etc/pam.d/runuser-l
PAM configuration file if \-\-login is specified
.TP
/etc/default/runuser
runuser specific logindef config file
.TP
/etc/login.defs
global logindef config file
.PD 1
.SH "SEE ALSO"
.BR pam (8),
.BR shells (5),
.BR login.defs (5),
.BR su (1)
.SH AUTHOR
Derived from coreutils' su which was based on an implemenation from
David MacKenzie and Fedora runuser command from Dan Walsh.
.SH AVAILABILITY
The runuser command is part of the util-linux package and is
available from
.UR ftp://\:ftp.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
Linux Kernel Archive
.UE .