I tried to implement the special number regex as such: 

#!/usr/bin/env perl 
use strict;
use warnings;
use Regexp::Common;

print "Enter limit: ";
chomp( my $limit = <STDIN> );
$limit = abs($limit);

open my $IN, '<', "xt_spacer_results.hairpin" or die $!;
open my $SIFTED, '>', "new_xt_spacer_results.hairpin" or die $!;

while (<$IN>){
    next if /^None/;
    next if /^( $RE{num}{real}{-places=>2})/ && $1 > $limit;
    print $SIFTED $_;
}

close $IN;
close $SIFTED;

[download]

But it aborts the program due to  use Regexp::Common; and it states:

Can't locate Regexp/Common.pm in @INC (@INC contains: /usr/local/lib64/perl5 /usr/local/share/perl5 /usr/lib64/perl5/vendor_perl /usr/share/perl5/vendor_perl /usr/lib64/perl5 /usr/share/perl5 .) at energy_sifter2.pl line 4. BEGIN failed--compilation aborted at energy_sifter2.pl line 4.

I'm not quite sure how to use modules. Do I download the module somehow and save it in the same file I'm working in?

In reply to Re^4: Easiest way to filter a file based on user input (updated) by Peter Keystrokes
in thread Easiest way to filter a file based on user input by Peter Keystrokes

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