Comment by catern

The only thing in this post that can be accurately called defensive is the use of "local" and "readonly". The rest is all just style preferences, which are rather subjective, and none of which are very appealing to me.

Three real defensive bash programming tips are:

- Quote all uses of variables

- set -o nounset

- set -o errexit

And many others can be found in and around http://mywiki.wooledge.org/BashFAQ