ROOT is an object-oriented program and library developed by CERN. It is a framework for data processing. "It was originally designed for particle physics data analysis and contains several features specific to this field, but it is also used in other applications such as astronomy and data mining." [ http://en.wikipedia.org/wiki/ROOT (27 June 2011)]
To exit the cint C++ interpreter, at the root prompt, enter: .q
To discover what version of ROOT are available, at the shell prompt, enter:
module avail cern_rootor,
module avail
To use a version other than the default production version, at the compute node shell prompt, enter:
module load cern_root/5.26.00
root
where cern_root/5.26.00 is one of the versions listed by the module avail command.
For more information, please refer to http://root.cern.ch. An extensive Users Guide is available from that site.