[Tim]
Well, that's in interactive mode, and I see sys.path[0] == "" on both Windows and Linux then. I don't see "" in sys.path on either box in batch mode, although I do see the absolutized path to the current directory in sys.path in batch mode on Windows but not on Linux -- but Mark Hammond says he doesn't see (any form of) the current directory in sys.path in batch mode on Windows.
It's a bit confusing ;-)
[Guido]
How did you test batch mode?
I gave full code (it's brief) and screen-scrapes from Windows and Linux yesterday: http://mail.python.org/pipermail/python-dev/2005-October/057162.html By batch mode, I meant invoking path_to_python path_to_python_script.py from a shell prompt.
All:
sys.path[0] is *not* defined to be the current directory.
It is defined to be the directory of the script that was used to invoke python (sys.argv[0], typically).
In my runs, sys.argv[0] was the path to the Python executable, not to the script being run. The directory of the script being run was nevertheless in sys.path[0] on both Windows and Linux. On Windows, but not on Linux, the _current_ directory (the directory I happened to be in at the time I invoked Python) was also on sys.path; Mark Hammond said it was not when he tried, but he didn't show exactly what he did so I'm not sure what he saw.
If there is no script, or it is being read from stdin, the default is ''.
I believe everyone sees that.