.TH SU 1 
.SH NAME
su  \-  substitute user id temporarily
.SH SYNOPSIS
.B su
[ userid ]
.SH DESCRIPTION
.I Su
demands the password of the specified
.I userid,
and if it is given,
changes to that 
.I userid
and invokes the Shell
.IR sh (1)
without changing the current directory or the
user environment (see
.IR environ (5)).
The new user ID stays in force until the Shell exits.
.PP
If no 
.I userid
is specified, `root' is assumed.
To remind the super-user of his responsibilities,
the Shell substitutes `#' for its usual prompt.
.SH "SEE ALSO"
sh(1)