use strict;
 use warnings;

 my $word  = shift || 'OLHOSC';
 my $fname = sprintf 'length%02d.txt', length $word; # eg. length06.txt
 my $word_key = join '', sort split //, lc $word;    # sort lowercase letters

 open my $fh, '<', $fname or die "sorry, no such word list available, Bye!";
 while( my $line = <$fh> ) {
    chomp $line;
    my $dict_key = join '', sort split //, lc $line;
    print "$word => $line\n" if $dict_key eq $word_key
    # bail out here - if only one match is needed
 }
 close $fh;