[tlug] Testing Apache for gzip modules

[Dave M G <dave@example.com>]

TLUG,

I'm trying to set up my web sites to use gzip compression and expires 
headers.
Naturally, I'm trying to learn from searching the web for instructions 
on exactly how to do that.
I found code to add to my .htaccess file, but it doesn't seem to be 
working, so I think maybe my host server doesn't have the right Apache 
modules enabled.
I think I need modules called mod_gzip and mod_expires.

This is where I've hit a wall. I can't figure out what commands to issue 
to confirm the presence or absence of the right modules.
I figure it should be easy, but I've come up with nothing.

Can someone point me in the right direction? To confirm the modules and 
enable them if they're not present?
Any advice would be much appreciated.

--
Dave M G