The following resources might be interesting if you'd like to go deeper into the subjects of this chapter:
- Hello World (long tutorial): https://bash.cyberciti.biz/guide/Hello,_World!_Tutorial
- Bash coding style guide: https://bluepenguinlist.com/2016/11/04/bash-scripting-tutorial/
- KISS: https://people.apache.org/%7Efhanik/kiss.html