We need a sample of the data since there are conditions on which we will not be checking diff's. However I would suggest something like the following.

#!/perl

use strict;
use warnings;

my @months = qw(January February March April May June July 
                August September October November December);

open(FIRST,  "<first.file")  or die "$!";
open(SECOND, "<second.file") or die "$!";

#if the files aren't huge you can slurp and comapre arrays

my @first  = <FIRST>;
my @second = <SECOND>;

close(FIRST);
close(SECOND);

open(DIFF, ">diff.file) or die "$!";

for(my $i = 0; $i < $#first; $i++)
{
     my $is_date = 0;
     foreach(@months)
     {
          if($first[$i] =~ m{$_\s*\d{1,2}})
          { 
             $is_date = 1;
             last;
          }
     }

     if(!$is_date)
     {
        if($first[$i] ne $second[$i])
        {
             print DIFF, "Difference found @ line: ".$i."\n";
             print DIFF, "File 1: ".$first[$i]."\n";
             print DIFF, "File 2: ".$second[$i]."\n";
             print DIFF, "----------------------------\n";
        }
     }
}
close(DIFF);
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But you should be more specific in your question, like show us some sample code, or sample files.

Text::Diff (and it's model, GNU diff) won't selectively ignore things; the poster needs to compare, but ignore differences in date. Unfortunately, a simple diff won't accomplish this.

One approach would be to load columnar data (date in one column) and ignore the date column while comparing the rest of the data using something like Array::Compare.

radiantmatrix
require General::Disclaimer;
"Users are evil. All users are evil. Do not trust them. Perl specifically offers the -T switch because it knows users are evil." - japhy

You are right, but I was thinking that the poster could do some post-processing of the diff output to discard the dates.

---

I'm not really a human, but I play one on earth. flash japh

Your example is actually incorrect. Because "A big bad witch lived inside" is what you expect to be seen as the same. However, they are on different lines, and thus not the same. Your output can only be true if no line will be repeated and you scan each file for each line in the other. ie

  
while(<ONE>)
{  
    my $line = $_;

    while(<TWO>)
    { 

         print "different" if (!/$line/);    
    }
}
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