> No, let's just try it out (I've put both the Python and the plain sh -c invocations):

  > python2 -c 'import os; os.system("-x")'
  > sh -c -x
  sh: -c: option requires an argument

I can't reproduce this in Python (including my local 2.7 build), only using sh directly. Going through Python, `sh` correctly tells me that the `-x` command isn't found.

But now I'm wondering: how is one supposed to use `which` (or `type`, or `file`) for a program named `-x`, supposing one had it?