[PapaSpaceDelta]

One reason is that any System Administrator can be expected to be able to understand and maintain Bash scripts.

I recently built a fairly complex system entirely in Bash, not because it was the "best" language for the job (it would have been much easier to do in Ruby or Python), but because the client didn't have any permanent staff that could maintain Ruby or Python scripts.

As a contractor, one of the major factors in the technical decisions I make is: how supportable is this technology for the client, once I have left? Of course the answer to that question will vary on a case by case basis, but Bash is usually a good lowest common denominator in a Linux environment.