sub encode {
    my $encode = shift;
    $encode =~ s/([^\w\s.!~*()'-=&])/sprintf "%%%02X", ord($1)/eg;
    $encode =~ tr/ /+/;
  return $encode;
}

sub decode {
    my $decode = shift;
    $decode =~ tr/+/ /;
    $decode =~ s/%([a-f\d][a-f\d])/pack("c",hex($1))/ige;
  return $decode;
}

$str = qq/Arnie said, "I'll be back!"/; 
$enc = encode ($str);
$dec = decode ($enc);
print "$enc\n$dec";