Sarg reads its configuration options from a configuration file whose path is hard coded during the [Build on Linux] stage. It is usually set to /etc/sarg/sarg.conf (--sysconfdir=/etc/sarg) but the ./configure script puts it in /usr/local/etc/sarg.conf if no --prefix nor --sysconfdir options are provided.
Sarg writes the full path to the current sarg.conf when it is ran with the -x command line option. Use that command line option to find out exactly which sarg.conf is taken into account.
The options are described in the sample sarg.conf distributed along with the sources and also in wiki, see [Configuration options] page.
Wiki: Build on Linux
Wiki: Configuration options
Wiki: Table of content