Regex syntax and features vary between implementations. \d isn't supported by BRE/ERE flavors.

GNU grep supports PCRE, so you can use grep -oP '/dev/loop\d' or grep -o '/dev/loop[0-9]' if you are matching only one digit character.

Well, if you are comfortable with Python scripts, there's not much reason to switch to awk. Unless perhaps you are equating awk to Python as scripting languages instead of CLI usage (like grep, sed, cut, etc) as my ebook focuses on. For example, if you have space separated columns of data, awk '{print $2}' will give you just the second column (no need to write a script when a simple one-liner will do). This of course also allows you to integrate with shell features (like globs).

As a practical example, I use awk to filter and process particular entries from financial data (which is in csv format). Just a case of easily arriving at a solution in a single line of code (which I then save it for future use).

I wish you success. I'm happy to use SimpleScreenRecorder(https://github.com/MaartenBaert/ssr).

I had to learn Linux CLI tools, Vim and Perl at my very first job. Have a soft spot for Perl, despite not using it much these days other than occasional one-liners (mainly for advanced regex features).

I have a list of curated resources here: https://learnbyexample.github.io/py_resources/

There are sections for beginners, intermediate, advanced, etc. Also included are exercises, projects, debugging, testing, and many more stuff. Hope it helps :)

EPUB reader

Check out https://github.com/auctors/free-lunch (list of free Windows software)

See also https://www.nirsoft.net/ (freeware, not open source)

Check out https://github.com/HollyAdele/awesome-programming-for-kids

I have a book for Perl One-Liners as well, which I'm currently revising :)

I've written books on regex too, if you are interested in learning ;)

I read three progression fantasy books in the past three days, so I'm going to take a break and get some of my actual work done :D

Card Mage: Slumdog Deckbuilder by Benedict Patrick (book 1 of a new series) was well written and a compelling read, but I'd have enjoyed it a lot more if it was lighthearted.

Overpowered Dungeon Boy by Benjamin Barreth (2 book completed series) was a lighthearted fun read. The OP main character took a while to warm up to, but many of the side characters were easy to root for.

I mostly read on Kindle Unlimited. A lot of the progression fantasy and cozy fantasy books are on KU (my current favorite subgenres), so there's no shortage of books to read. In addition, there's plenty of self-pub fantasy and sci-fi books (there are two competitions: SPFBO and SPSFC which help in finding good ones to read).