I installed maven on my Ubuntu machine with the command sudo apt-get install maven
Now I need to know where it is installed in order to configure the same in IntelliJ..
Ubuntu, which is a Debian derivative, follows a very precise structure when installing packages. In other words, all software installed through the packaging tools, such as apt-get or synaptic, will put the stuff in the same locations. If you become familiar with these locations, you'll always know where to find your stuff.
As a short cut, you can always open a tool like synaptic, find the installed package, and inspect the "properties". Under properties, you'll see a list of all installed files. Again, you can expect these to always follow the Debian/Ubuntu conventions; these are highly ordered Linux distributions. IN short, binaries will be in /usr/bin, or some other location on your path ( try 'echo $PATH' on the command line to see the possible locations ). Configuration is always in a subdirectory of /etc. And the "home" is typically in /usr/lib or /usr/share.
For instance, according to http://www.mkyong.com/maven/how-to-install-maven-in-ubuntu/, maven is installed like:
The Apt-get installation will install all the required files in the following folder structure
/usr/bin/mvn
/usr/share/maven2/
/etc/maven2
P.S The Maven configuration is store in /etc/maven2
Note, it's not just apt-get that will do this, it's any .deb package installer.