The default Gnu compilers on the CSC clusters is 4.4, but sometimes codes require a more recent compiler, 4.8 being common.

You can use Gnu 4.8 by typing:

source /opt/rh/devtoolset-2/enable

You can verify this worked by typing

gcc -v

and you will see something like this: gcc version 4.8.2 20140120 (Red Hat 4.8.2-15) (GCC)

Also, if you need a more recent 'cmake' than 2.6, you can simply type

cmake28

to use a more recent version.