I don't think tying is going to help you the way you hope it will.

You're still going to have to write the methods or subs that open the text files and search through and aggregate your data (which is what you were trying to avoid.) All tying does is give you a nice, clean, familiar interface to use (although nothing you can't do outside of tying.) In other words, if you tie a hash, you'd be able to access your data like

  tie %hash, 'MyHashClass', @files;
  my @data = $hash{$key};                # convienent!
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but somewhere in the background you'll still need something like

package MyHashClass;
use strict;
use Carp;
use Tie::Hash;

@MyHashClass::ISA = qw/ Tie::StdHash /;

sub FETCH {
  my ($self, $key) = @_;
  my @ret = ();

  foreach my $filename ( @files ) {
    open( F, $filename ) or croak "$!";
    while( <F> ) {
      if ( matches ) { push @ret, $_; }
    }
    close F;
  }

  return @ret;
}
1;
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Hmm. Actually this is horribly inefficient and you wouldn't want to do it this way. You'd probably open all of the files when the hash is tied or something.

But I think I'm getting off track. I guess my point is that tying isn't going to save you any work.

If you have a lot of data or you're going to have to search through it very often, it's worth combining and/or sorting your files (or converting to a database like Berkeley DB (DB_File)) so you can search them more efficiently. Otherwise doing what you say (open each one, pull the appropriate row, etc.) will work.