#! /usr/bin/perl use strict; use warnings; open SIG, 'signal.txt' ; my @sig = ; close SIG ; chomp @sig ; open ORD, 'orderednames.txt' ; my @ord = ; close ORD ; my @names = map { split } @ord ; my %names_hash ; $names_hash{$_} = 1 foreach @names ; my @results = grep { !$names_hash{$_} } @sig ; print join( ':', @results ), "\n" ;