Pro Bash: Learn to Script and Program the GNU/Linux Shell

© The Author(s), under exclusive license to APress Media, LLC, part of Springer Nature 2023

J. VarmaPro Bash https://doi.org/10.1007/978-1-4842-9588-5_3

3. Looping and Branching

Jayant Varma¹  

(1)

Berwick, VIC, Australia

 

At the heart of any programming language are iteration and conditional execution. Iteration is the repetition of a section of code until a condition changes. Conditional execution is making a choice between two or more actions (one of which may be to do nothing) based on a condition.

In the shell, there are three types of loops (while, until, and for) and three types of conditional execution (if, case, and the conditional operators && and ||, which mean AND and OR, respectively). Except for for and case, the exit status of a command ...