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SU(1)			FreeBSD	General	Commands Manual			 SU(1)

NAME
     su	-- substitute user identity

SYNOPSIS
     su	[-Kflm]	[login]

DESCRIPTION
     Su	requests the Kerberos password for login (or for ``login.root'', if no
     login is provided), and switches to that user and group ID	after obtain-
     ing a Kerberos ticket granting ticket.  A shell is	then executed.	Su
     will resort to the	local password file to find the	password for login if
     there is a	Kerberos error.	 If su is executed by root, no password	is
     requested and a shell with	the appropriate	user ID	is executed; no	addi-
     tional Kerberos tickets are obtained.

     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
     target login's.  This is the traditional behavior of su.

     The options are as	follows:

     -K	     Do	not attempt to use Kerberos to authenticate the	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 environ-
	     ment.  The	invoked	shell is the target login's, and su will
	     change directory to the target login's home directory.

     -m	     Leave the environment unmodified.	The invoked shell is your
	     login shell, and no directory changes are made.  As a security
	     precaution, 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 0 (normally ``wheel'')	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), 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.

FreeBSD	11.1			April 18, 1994			  FreeBSD 11.1

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | ENVIRONMENT | HISTORY

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