The subprocess module provides a good foundation of basic functionality.  However, anything moderately complex becomes cumbersome to write.  Additionally, it has pitfalls that people frequently overlook.

People then often either resort to hand-rolling their own abstraction on top of it, use the library incorrectly, or just use shell scripts if the predominant action is to stitch things together.

I have seen great success at avoiding having to write shell-scripts & using the sh package. What once would have been written as shell-scripts now can be written very naturally using sh in a more maintainable & reusable manner.

I think sh being part of the standard library would be a great addition & make python even more compelling as a replacement for shell scripts.  Having sh be part of the python library also ensures that the `with` syntax could be done in a comprehensive thread-safe manner.

https://pypi.python.org/pypi/sh
http://amoffat.github.com/sh