Version of Apache installed on a Debian machine
Try apachectl -V:
$ apachectl -VServer version: Apache/2.2.9 (Unix)Server built: Sep 18 2008 21:54:05Server's Module Magic Number: 20051115:15Server loaded: APR 1.2.7, APR-Util 1.2.7Compiled using: APR 1.2.7, APR-Util 1.2.7... etc ...If it does not work for you, run the command with sudo.
You should use apache2ctl -v or apache2 -v for newer Debian or Ubuntu distributions.
apache:/etc/apache2# apache2ctl -vServer version: Apache/2.2.16 (Debian)Server built: May 12 2011 11:58:18or you can use apache2 -V to get more information.
apache2 -VServer version: Apache/2.2.16 (Debian)Server built: May 12 2011 11:58:18Server's Module Magic Number: xServer loaded: APR 1.4.2, APR-Util 1.3.9Compiled using: APR 1.2.12, APR-Util 1.3.9Architecture: 64-bitServer MPM: Worker threaded: yes (fixed thread count) forked: yes (variable process count)Server compiled with....