Wget HEAD request?
It's not wget, but you can do that quite easily by using curl.
curl -I http://www.superuser.com/
Produces this output:
HTTP/1.1 301 Moved Permanently
Content-Length: 144
Content-Type: text/html; charset=UTF-8
Location: http://superuser.com/
Date: Sat, 09 Oct 2010 19:11:50 GMT
Try:
wget -S --spider www.example.com
You can also pass -O /dev/null
to prevent wget
from writing HTTP response to a file.
There isn't any need for curl.
With Wget, adding --spider
implies that you want to send a HEAD
request (as opposed to GET
or POST
).
This is a great minimalistic way of checking if a URL responds or not. You can for example use this in scripted checks, and the HEAD
operation will make sure you do not put any load on neither the network nor the target webserver.
Bonus information: If Wget gets an HTTP error 500 from the server when it performs the HEAD
it will then move on to perform a GET
against the same URL. I don't know the reasoning for this design. This is the reason why you may see both a HEAD
and a GET
request being performed against the server. If nothing is wrong then only a HEAD
request is performed. You can disable this functionality with the --tries
option to limit Wget to only one attempt.
All in all, I recommend this for testing if an URL is responding:
# This works in Bash and derivatives
wget_output=$(wget --spider --tries 1 $URL 2>&1)
wget_exit_code=$?
if [ $wget_exit_code -ne 0 ]; then
# Something went wrong
echo "$URL is not responding"
echo "Output from wget: "
echo "$wget_output"
else
echo "Check succeeded: $URL is responding"
fi