.TH SU 1 ubase-VERSION
.SH NAME
\fBsu\fR - Run a command with a substitute user and group ID
.SH SYNOPSIS
\fBsu\fR [\fB-lp\fR] [\fIusername\fR]
.SH DESCRIPTION
\fBsu\fR allows to run commands with a substitute user and group ID.
When called without arguments, su defaults to running an interactive shell
as root.  For backward compatibility su defaults to not change the current
directory and to only set the environment variables \fBHOME\fR and \fBSHELL\fR
(plus \fBUSER\fR and \fBLOGNAME\fR if the target \fIusername\fR is not root).
.SH OPTIONS
.TP
\fB-l\fR
Starts the shell as login shell with an environment similar to a real
login.
.TP
\fB-p\fR
Preserves the whole environment.  This option is ignored if the \fB-l\fR
option is specified.