Scripting

9.3    Regular Expressions in Bash (grep, sed)

You should now understand the basic principles of regular expressions. Let me point out again that, in the previous section, I only outlined the most important syntax rules. Whole books of hundreds of pages are available that focus exclusively on this subject, covering every conceivable variation.

In this and the following sections, we want to look at the application of regular expressions. At this point, I’ll start with Bash, focusing mostly on the grep and sed commands.

9.3.1    Bash Comparison Operator for Regular Expressions

In an elementary way, Bash and Zsh can process regular patterns without external tools. For this purpose, you can use the =~ comparison operator, which you must apply in ...