The help center [states][1] that (emphasis mine):

> Using and administering official Ubuntu flavors including: Edubuntu, Ubuntu GNOME, Kubuntu, Ubuntu Kylin, Lubuntu, Mythbuntu, Ubuntu Studio, Xubuntu, Ubuntu Touch and Ubuntu MATE.

Shell scripting is an essential part of administering (and using, really) a Linux system. Including Ubuntu. 

We also have a [meta discussion][2] that has been well accepted and which states that:

> Bash is the default shell on Ubuntu. Shell scripting is an integral part of managing a Linux system. I believe that all bash related questions are on-topic, even the ones that have to do clearly with programming tasks like how to add 1 to a variable.

As far as I can tell, these all mean that bash questions, _any_ bash questions are welcome and on topic here. This should also apply to any other shell since they are all basic Linux tools and are easily available on Ubuntu. In any case, bash most certainly is on topic.


To illustrate, we currently have 

* 2,848 questions tagged with [tag:bash]
* 83 questions tagged with [tag:zsh]
* 21 questions tagged with one of [tag:ksh],[tag:tcsh] or [tag:csh].
* 46 questions tagged with [tag:scripting]
* 537 questions tagged with [tag:shell-scripting]
* 1,553 questions tagged with [tag:scripts]
* 1,722 questions tagged with [tag:python]

So, in conclusion, yes shell scripting questions are perfectly on topic and welcome here. Please stop closing such questions as off topic. 
  [1]: http://askubuntu.com/help/on-topic
  [2]: http://meta.askubuntu.com/q/10317/85695