Making Programs Executable

[VanL]

In addition to having the execute bit set, you can 
occasionally run into errors ir you have edited the file on 
a windows box:

In vi, instead of

!#/usr/bin/env python

you will see

!#/usr/bin/env python^M

which can give some inexplicable errors when trying to run 
the script directly, as opposed to specifying the 
interpreter.  Sometimes shells can be maddeningly literal.

-VanL