#!/usr/local/bin/perl -w use strict; open (FILE1,"Largedatafile.txt"); open (FILE2,"Smalldatafile.txt"); open (FILE3,"addressfile.txt"); while() { ($var1, $var2, $var3,$var4,$var5)=split(/\t/, $_); { while() { ($id1, $id2,$id3)=split(/\t/,$_); while() { ($citycode, $statecode,$zipcode)=split(/\t/,$_); if (($id3 != $var3) & ($citycode !=$var5)) { print "$var1\tid1\n"; } } } } } close (FILE1); close (FILE2); close (FILE3);