#!/usr/bin/env perl
 
use warnings;
use strict;

use Digest::MD5;

sub md5sum{
  my $file = shift;
  my $digest = "";
  eval{
    open(FILE, $file) or die "[ERROR] md5sum: Can't find file $file\n";
    my $ctx = Digest::MD5->new;
    $ctx->addfile(*FILE);
    $digest = $ctx->hexdigest;
    close(FILE);
  };
  if($@){
    print $@;
    return "";
  }
  return $digest;
}
sub usage{
  print "usage: ./md5sum.pl filename\n";
  exit 1;
}
if($#ARGV + 1 != 1){
  usage();
}
my $fname = $ARGV[0];
my $md5 =  md5sum($fname);
if($md5 ne ""){
  print $md5." ".$fname."\n";
}else{
  exit 1;
}

exit 0;