opendarwin man page for su

SU(1)							    BSD General Commands Manual 						     SU(1)

NAME
     su -- substitute user identity

SYNOPSIS
     su [-flm] [login] [-c shell arguments]

DESCRIPTION
     su requests the password for login and switches to that user and group ID after obtaining proper authentication.  A shell is then executed,
     and any additional shell arguments after the login name are passed to the shell.  If su is executed by root, no password is requested and a
     shell with the appropriate user ID is executed.

     The options are as follows:

     -c      Invoke the following command in a subshell as the specified user.

     -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.  This option is identical to
	     just passing "-", as in "su -".

     -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 and -m options are mutually exclusive; the last one specified overrides any previous ones.

     Only users in group ``wheel'' (normally gid 0) or group ``admin'' (normally gid 20) can su to ``root''.

     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.

SEE ALSO
     csh(1), login(1), sh(1), skey(1), kinit(1), kerberos(1), passwd(5), group(5), environ(7)

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).

HISTORY
     A su command appeared in Version 7 AT&T UNIX.

BSD
								  April 18, 1994							       BSD