SVN
Installation
Before using subversion (checking out code/FOG) you need to install the proper package on your system first.
Debian/Ubuntu:
sudo apt-get update && apt-get install subversion
CentOS/Fedora/RHEL:
sudo yum update && yum install subversion
Checkout
cd ~ svn checkout https://svn.code.sf.net/p/freeghost/code/trunk fogproject cd fogproject ...
You'll find detailed instructions on how to install FOG here.
GUI Subversion clients
Coming from a Windows background, some people may prefer using a GUI Subversion client, rather than the standard, basic command-line client. If you feel comfortable with a file system browser/explorer integrated Subversion client, then TortoiseSVN is the best choice - it is extremely popular.
Another tool that is simple to configure and easy to understand, but is a traditional one-window application like Microsoft ™ Visual Source Safe ™ is RapidSVN. It is cross-platform and has a simple interface, in one place unlike TortoiseSVN.