wget GET vs HEAD

[Peng Yu]

Hi,

I'd like to understand the following two commands. One uses GET, the
other uses HEAD.

wget -q -O /dev/null -S -o- URL
wget -q --spider -S -o- URL

Is there first still download response body? Does wget know that its
/dev/null so that it just download the header and ignore the response
body?

If I only want the reponse header, and GET and HEAD result in the same
header for my purpose, I should use the 2nd one to save time as it
does not have response body?

Thanks.

-- 
Regards,
Peng