>type crickson.pl use strict; use warnings; my $arg = \'$infile1'; my $infile1 = \"one_score\t999"; my $score=100000; open my $IN, '<', $arg or die "error opening list of files"; while (<$IN>) { $_ = eval $_; # Bad practice - Use only for 'in-memory' file. open my $IN1, '<', $_ or die "error opening file $_"; while (local $_ = <$IN1>) { my @temp = split /\t/; if ($temp[1] < $score) { warn "\$temp[1] not defined\n" if !defined $temp[1]; warn "\$score not defined\n" if !defined $score; print "$temp[1] < $score\n"; } } } >perl crickson.pl 999 < 100000 >