#!perl
use strict;
my $fixlen = 5;
my @words = qw( s so som some somew somewo somewor someword somewords);
foreach my $word (@words) {
  $word =~ s/^(.{1,$fixlen}).*$/pack "A$fixlen", $1/e;
  print ">$word<\n";
}
__END__
>s    <
>so   <
>som  <
>some <
>somew<
>somew<
>somew<
>somew<
>somew<