use warnings; use strict; open inFile, '<', "accts_to_exclude.txt" || die "Cannot open accts_to_exclude.txt"; my %excludeList = map {chomp; $_ => undef} ; close inFile; open inFile, '<', "list1.txt" || die "Cannot open list1.txt"; my %acctList = map {chomp; $_ => undef} ; close inFile; open inFile, '<', "list2.txt" || die "Cannot open list2.txt"; my %diffList = map {chomp; $_ => undef} ; close inFile; open inFile, '<', "list3.txt" || die "Cannot open list3.txt"; my %nameList = map {chomp; $_ => undef} ; close inFile; open orgAcctList, '<', "orig_accts.txt" || die "Cannot open orig_accts.txt"; open outFile, '>', 'output.txt' || die "Cannot open output file output.txt"; while (my $line = ){ chomp $line; my ($filename, $state, $amt, $ttl, $account, $name, $invnum) = split /\t/, $line; next if exists $excludeList{$account}; print outFile "$filename $state $amt $ttl $account $name $invnum\n"; if (defined $acctList{$account}) { # do something (write this info to file1) next; } if (defined $diffList{$account}) { # do something (write this info to file2¡K) next; } if (defined $nameList{$name}) { # do something (write this info to file2) last; } }