NAME
su - substitute user id temporarily

SYNOPSIS
su [ -f ] [ - ] [ userid [ args ] ]

DESCRIPTION
Su demands the password of the specified userid, and if it is
given, changes to that userid and invokes the shell of that user
without changing the current directory. The user environment is
unchanged except for HOME and SHELL, which are taken from the
password file for the user being substituted (see environ(7)). The
new user ID stays in force until the shell exits. If no userid is
specified, "root" is assumed.

The -f option prevents csh(1) from executing the .cshrc file; thus
making su start up faster.

The - option simulates a full login.

The args are passed along as arguments to the shell or command
being invoked.

SEE ALSO
sh(1), csh(1)