The KISS principle is a great way to approach shell scripting. While it might come across as a bit harsh, the spirit in which it is given is important: it should only be considered great advice. Further advice is given in the Zen of Python, the design principles on which Python rests:

• Simple is better than complex
• Complex is better than complicated
• Readability counts

There are about 17 more aspects in the Zen of Python, but these three are the most relevant for Bash scripting as well. The last one, 'Readability counts', should be obvious by now. However, the first two, 'Simple is better than complex' and 'Complex is better than complicated' are closely related to the KISS principle. Keeping things simple is a great goal, but if that is not possible, a complex solution is always better than a complicated one (no one likes complicated scripts!).

There are a few things you can keep in mind when writing scripts:

• If the solution you're cooking up seems to get very complicated, do either of the following things:
  • Research your problem; perhaps there is another tool you can use instead of what you are using now.
  • See whether you can split things into discrete steps, so it gets more complex but less complicated.
• Ask yourself if you need everything on a single line, or if it is perhaps possible to split the command over multiple lines to increase readability. When using pipes or other forms of redirection, as explained in greater detail in Chapter 12, Using Pipes and Redirection in Scripts, this becomes something to keep in mind.
• If it works, it's probably not a bad solution. However, make sure that the solution is not too simple, since edge cases might cause trouble later on.