The pylib installs several scripts to support testing and (python) development. If working from a checkout you may also add bin to your PATH environment variable which makes the scripts available on your shell prompt.
The py.test executable is the main tool that the py lib offers; in fact most code in the py lib is geared towards supporting the testing process. See the py.test documentation for extensive documentation. The py.test-$VERSION is the same script with an interpreter specific suffix appended to make several versions of py.test for using specific interpreters accessible:
Usage: py.which modulename
Print the __file__ of the module that is imported via import modulename. The version-suffix is the same as with py.test above.
Usage: py.cleanup [PATH]
Delete pyc file recursively, starting from PATH (which defaults to the current working directory). Don't follow links and don't recurse into directories with a ".".
Usage: py.countloc [PATHS]
Count (non-empty) lines of python code and number of python files recursively starting from a PATHS given on the command line (starting from the current working directory). Distinguish between test files and normal ones and report them separately.
Usage: py.lookup SEARCH_STRING [options]
Looks recursively at Python files for a SEARCH_STRING, starting from the present working directory. Prints the line, with the filename and line-number prepended.