Hopefully this helps!

Not entirely, perhaps...

... a suffix of n digits. Now that I think about it, you can ignore the suffix altogether and just replace the n digits with *.

Well, I'm assuming there must be some other constraint (which you haven't described yet) that would make this an inadequate solution:

my %collapsed;
opendir( D, "/whatever/path" ) or die "whatever: $!\n";

for my $name ( grep /\d+$/, readdir D ) {
    $name =~ s/\d+$/*/;
    $collapsed{$name}++;
}

for my $name ( sort keys %collapsed ) {
    print "$name\n";
}
[download]

If you're trying to do something else besides ignoring the final digits -- if there's supposed to be some actual structure to the file names and you need to do something with that besides adding "*" at the end -- let us in on it. From what you've described so far, it's either too simple or too vague.