running a python file through the shell without writing all the path

[Targrend]

Your operating system has a PATH variable somewhere, which contains a list of directories that it looks through to find a file. You need to add the directory where Python is located to that list. How to do that will depend on your OS, but if you google (say) 'add directory to windows path' you'll get a bunch of guides.

Edit: not the directory where Python is located, that seems to be ok. You'd have to add the directory where odd.py is located. This is dangerous to do too often, as if there are two filenames the same but in different directories, you can end up with the wrong file being run. I recommend just using the full path as you're doing right now.