su(1) [osx man page]
SU(1) BSD General Commands Manual SU(1) NAME
su -- substitute user identity SYNOPSIS
su [-] [-flm] [login [args]] DESCRIPTION
The su utility requests appropriate user credentials via PAM and switches to that user ID (the default user is the superuser). A shell is then executed. PAM is used to set the policy su(1) will use. In particular, by default only users in the ``admin'' or ``wheel'' groups can switch to UID 0 (``root''). This group requirement may be changed by modifying the ``pam_group'' section of /etc/pam.d/su. See pam_group(8) for details on how to modify this setting. By default, the environment is unmodified with the exception of USER, HOME, and SHELL. HOME and SHELL are set to the target login's default values. USER is set to the target login, unless the target login has a user ID of 0, in which case it is unmodified. The invoked shell is the one belonging to the target login. This is the traditional behavior of su. The options are as follows: -f If the invoked shell is csh(1), this option prevents it from reading the ``.cshrc'' file. -l Simulate a full login. The environment is discarded except for HOME, SHELL, PATH, TERM, and USER. HOME and SHELL are modified as above. USER is set to the target login. PATH is set to ``/bin:/usr/bin''. TERM is imported from your current environment. The invoked shell is the target login's, and su will change directory to the target login's home directory. - (no letter) The same as -l. -m Leave the environment unmodified. The invoked shell is your login shell, and no directory changes are made. As a security precau- tion, if the target user's shell is a non-standard shell (as defined by getusershell(3)) and the caller's real uid is non-zero, su will fail. The -l (or -) and -m options are mutually exclusive; the last one specified overrides any previous ones. If the optional args are provided on the command line, they are passed to the login shell of the target login. Note that all command line arguments before the target login name are processed by su itself, everything after the target login name gets passed to the login shell. By default (unless the prompt is reset by a startup file) the super-user prompt is set to ``#'' to remind one of its awesome power. ENVIRONMENT
Environment variables used by su: HOME Default home directory of real user ID unless modified as specified above. PATH Default search path of real user ID unless modified as specified above. TERM Provides terminal type which may be retained for the substituted user ID. USER The user ID is always the effective ID (the target user ID) after an su unless the user ID is 0 (root). FILES
/etc/pam.d/su PAM configuration for su. EXAMPLES
su man -c catman Runs the command catman as user man. You will be asked for man's password unless your real UID is 0. su man -c 'catman /usr/share/man /usr/local/man' Same as above, but the target command consists of more than a single word and hence is quoted for use with the -c option being passed to the shell. (Most shells expect the argument to -c to be a single word). su -l foo Simulate a login for user foo. su - foo Same as above. su - Simulate a login for root. SEE ALSO
csh(1), sh(1), group(5), passwd(5), environ(7), pam_group(8) HISTORY
A su command appeared in Version 1 AT&T UNIX. BSD
September 13, 2006 BSD
Check Out this Related Man Page
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 seman- tics 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 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 -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.) -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. 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. 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 com- mand 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)