The error 'command not found' means that the command is not found in the $PATH environment variable.
If you installed blender as described in the Wiki Installing Blender on Mac. The executable blender
is located in /Applications/Blender/blender.app/Contents/MacOS
You could simply open your terminal and enter
cd /Applications/Blender/blender.app/Contents/MacOS
./blender
ndof: 3Dx driver not found
found bundled python: /Applications/Blender/blender.app/Contents/MacOS/2.68/python
In order to run blender from any other location you would need to follow the instructions from DirectoryLayout Configuration & Data PathsDirectoryLayout Configuration & Data Paths
More Environment Variables
Run ./blender --help
Environment Variables:
$BLENDER_USER_CONFIG Directory for user configuration files.
$BLENDER_USER_SCRIPTS Directory for user scripts.
$BLENDER_SYSTEM_SCRIPTS Directory for system wide scripts.
Directory for user data files (icons, translations, ..).
$BLENDER_SYSTEM_DATAFILES Directory for system wide data files.
$BLENDER_SYSTEM_PYTHON Directory for system python libraries.
$TMP or $TMPDIR Store temporary files here.
$SDL_AUDIODRIVER LibSDL audio driver - alsa, esd, dma.
$PYTHONHOME Path to the python directory, eg. /usr/lib/python.