Command to check mod_pagespeed

Command to check mod_pagespeed is installed in server.

curl -D http://127.0.0.1

You will get below output.

Date: Fri, 07 Sep 2012 21:51:06 GMT
Server: Apache/2.2.3 (CentOS)
X-Mod-Pagespeed: 0.10.22.4-1633