#!/usr/bin/env perl 
use strict;
use warnings;

my @cases = qw/ABA SCO ACC PHC GHF/;
my $re = join '|', @cases;

for my $text ('SCO', 'Microsoft') {
    print "$text found (grep)\n" if grep {$text eq $_} @cases;
    print "$text found (regex)\n" if $text =~ /^$re$/;
}