use Digest::MD5;

    my $file = shift || "/etc/passwd";
    open(FILE, $file) or die "Can't open '$file': $!";
    binmode(FILE);

    print Digest::MD5->new->addfile(*FILE)->hexdigest, " $file\n";

use Digest::MD5;
use Digest::SHA1;
use Benchmark;
my $md5 = Digest::MD5->new();
my $sha1 = Digest::SHA1->new();
open FILE,'<',$0 or die $!;
binmode FILE;


sub check_md5 {
  $md5->addfile(*FILE)->hexdigest(),"\n";
}

sub check_sha1 {
  $sha1->addfile(*FILE)->hexdigest(),"\n";
}

timethese(10_000_000,{
  'Digest::MD5'=> \&check_md5,
  'Digest::SHA1' => \&check_sha1
  }
);
_ _ END _ _
Benchmark: timing 10000000 iterations of Digest::MD5, Digest::SHA1...
Digest::MD5: 27 wallclock secs (26.73 usr + -0.01 sys = 26.72 CPU) @ 374251.50/s (n=10000000)
Digest::SHA1: 43 wallclock secs (43.20 usr +  0.00 sys = 43.20 CPU) @ 231465.41/s (n=10000000)