Learn Linux Shell Scripting - Fundamentals of Bash 4.4

Using regular expressions in tests

A chapter after introducing if-then-else, we learned all about regular expressions. That chapter, however, was mostly theoretical and only contained a single script! Now, as you might realize, regular expressions are mostly supporting constructs that are to be used with other scripting tools. In the case of the tests we have described, we can use both globbing and regular expressions within the [[...]] blocks! Let's look at this in more depth, as follows:

reader@ubuntu:~/scripts/chapter_11$ vim square-number.sh reader@ubuntu:~/scripts/chapter_11$ cat square-number.sh #!/bin/bash###################################### Author: Sebastiaan Tammer# Version: v1.0.0# Date: 2018-10-26# Description: Return the square ...