cmd2 can be installed from PyPI by easy_install or pip.
Development trunk can be downloaded with mercurial:
hg clone http://hg.assembla.com/python-cmd2
To install from the trunk, cd python-cmd2 and run python setup.py install or python setup.py develop (requires setuptools). (Use root account, or sudo, on *nix.)
The Python 3 egg downloaded from PyPI or installed by pip or easy_install is ready to go.
To install from source for Python 3, the 2to3 transformations must be applied to cmd2.py. The best way to do this is to install distribute on Python 3 before installing cmd1:
curl -O http://python-distribute.org/distribute_setup.py sudo python3 distribute_setup.py sudo python3 setup.py install
2to3 won't run if there's a build directory that's newer than your source code. Deleting the cmd2/build directory before running setup.py ensures that this won't be a problem.