find dir1 dir2 -type f -print0 | xargs -0 md5sum >md5sums

##</code><code>##

chkmd5 md5sums

##</code><code>##

#!/usr/bin/perl -ln 
use strict;
use warnings;
use Digest::MD5;
use Cwd;
use File::Basename;

BEGIN { our $base=cwd }

if ($. == 1) {
    chdir $_ or warn "Can't chdir to `$_': $!"
      for dirname $ARGV;
}

s/(\w{32})\s+// or 
  die "input data may not be in the correct format";
my $orig=$1;
warn("[$ARGV] `$_' doesn't exist!\n"), next unless -e;

open my $fh, '<:raw', $_ or 
  warn("Can't open `$_': $!\n"), next;
my $new=Digest::MD5->new->addfile($fh)->hexdigest;

warn "[$ARGV] md5sum mismatch for `$_'\n" 
  unless $orig eq $new;

close ARGV and chdir our $base if eof;

__END__