use strict;
use warnings;

# First things first.  If I can't figure out who you are, you're outta here.
my $editor;
if ( exists( $ENV{REMOTE_USER} ) ) {
    ($editor) = $ENV{REMOTE_USER} =~ m/(some regex)/i;
}
(defined $editor) || die "I can't determine who you are, so you can't access this area.";

#use editor later throughout the program