How to check mod_headers and mod_expires modules enabled in apache
On Ubuntu you can see the list of enabled modules here,
/etc/apache2/mods-enabled
All the above answers are wrong. Use instead:
apachectl -t -D DUMP_MODULES
or
apachectl -M
On Debian:
user@machine:~$ /usr/sbin/apache2 -l
Most GNU/Linux distros:
user@machine:~$ /usr/sbin/httpd -l
Ubuntu:
user@machine:~$ ls /etc/apache2/mods-enabled
On Mac OSX:
user@mymac:~$ httpd -l
On Win 7 (64-bit):
C:\Users\myuser>"\Program Files (x86)\Apache Software Foundation\Apache2.2\bin\httpd.exe" -l
Try these commands from a terminal window in all but Windows, which will use CMD instead.