johngg@aleatico:~$ perl -Mstrict -Mwarnings -E '
my $str    = q{example.me};
my $length = length $str;
my $padTo  = 4;
my $rem    = $length % $padTo;
my $padLen = $length + ( $rem ? $padTo - $rem : 0 );
print pack qq{Z$padLen}, $str;' | hexdump -C
00000000  65 78 61 6d 70 6c 65 2e  6d 65 00 00              |example.me..|
0000000c