You can get the Apache version currently running on  your webserver by the following shell commands.
Get Apache version on CentOS / Redhat
$> /usr/sbin/httpd -v
Get Apache version on Ubuntu
$> /usr/sbin/apache2 -v
You can get the Apache version currently running on  your webserver by the following shell commands.
$> /usr/sbin/httpd -v
$> /usr/sbin/apache2 -v