Rats! You beat me to the punch (post?) again choroba and haukex. Your guys code-foo is strong.

UPDATE: Ah, but mine does keep his specified formatting, so I'm claiming the bonus points :-).

Well, here is my solution anyway. I'm a lot more long winded with my code than the other monks here...

#!/usr/bin/perl
use warnings;
use strict;

@ARGV or die "No input file specified";

open my $first, '<', $ARGV[0] or die "Unable to open input file: $!";
open my $second, '<', $ARGV[1] or die "Unable to open input file: $!";

chomp(my @first_lines = <$first>);
chomp(my @second_lines = <$second>);

close $first;
close $second;

foreach (@first_lines)
{
    my ($line_letter, $range) = split;
    my ($range1_low, $range1_high) = split /-/, $range;
    
    my $output_line;
    foreach (@second_lines)
    {
        my ($range2_low, $range2_high) = split /-/, $_;
        
        my ($current_match, $first_match);
        foreach my $range2_value ($range2_low..$range2_high)
        {
            last if ($range2_value > $range1_high);
            next if ($range2_value < $range1_low);
            if (($range2_value >= $range1_low) && ($range2_value <= $r
+ange1_high))
            {
                $first_match = $range2_value if (!defined $current_mat
+ch);
                $current_match = $range2_value;
            }
        }
        
        $output_line .= "$first_match-$current_match, " if ((defined $
+current_match) && ($current_match != $first_match));
        $output_line .= "$first_match, " if ((defined $first_match) &&
+ ($current_match == $first_match));
    }
    
    if(defined $output_line)
    {
        substr($output_line, length($output_line)-2, 2) = "";
        print "$line_letter $output_line\n";
    }
}
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