=over

=item $EFFECTIVE_USER_ID

=item $EUID

=item $>

The effective uid of this process.  Example:

    $< = $>;		# set real to effective uid
    ($<,$>) = ($>,$<);	# swap real and effective uid

(Mnemonic: it's the uid you went I<TO>, if you're running setuid.)
Note: "C<$E<lt>>" and "C<$E<gt>>" can be swapped only on machines
supporting setreuid().

=back