This program requires the SBCL Common Lisp system (http://www.sbcl.org) to compile. Because of its use of a new feature of SBCL, "(save-lisp-and-die :executable t)", vcs-tree requires SBCL version 0.9.4 or greater to compile Once you have SBCL installed on your system, you can give the command make which will create the executable file "_vcs-tree". You can then copy that file to any directory in your path, such as /usr/local/bin/ Additionally, the small shell wrapper "vcs-tree" can be used and copied to a directory of binaries along with _vcs-tree.