python command line programming examples, recipes

Question

There has been a need for python command line utilities at work lately and I have no experience in writing cli's. Regardless, I must still pop them out.

My biggest hurdle is the structure of these programs. Also, the method in getting and verifying input from the user. I have been ending up with very looong while loops and I just dont think that is the most efficient approach.

Could someone provide links to open source cli programs that I may pick to gain a bit of an understanding? Or, books, tutorials, etc that I could get my hands on. I have dug around but have had little success (my google skills must be lacking).

Answer 1

I like baker. You use it like so:

% cat my.py
import baker


@baker.command
def cmd(start, end):
    print '%s %s' % (start, end)


if __name__ == '__main__':
    baker.run()

% python my.py cmd 2010-12-01 2010-12-31
2010-12-01 2010-12-31

Answer 2

Random hints:

• the optionparser module is good for parsing complex options
• many python modules indeed are cli programs. See there (for example, see python2.6/json/tool.py which you can run with python -m json.tool)

It is a good idea to use

 def main(arguments):
     etc.

 if __name__ == '__main__':
     # only if we are executed rather than imported as a module:
     import sys
     main(sys.argv)

Such that the parts of yor app can be reused by simply importing them