use strict;
use warnings;

my $file = '...';

open(my $fh, '<', $file)
   or die("Unable to open file \"$file\": $!\n");

my $reader = Reader->new($fh);
while (defined(my $line = $reader->get_line())) {
   $line =~ s/\S{40,}/.../g;
   print($line);
}