I have a list of learning resources for CLI tools and scripting here: https://learnbyexample.github.io/curated_resources/linux_cli_scripting.html
I've also written a few TUI interactive apps to practice text processing commands like grep, sed, awk, coreutils, etc: https://github.com/learnbyexample/TUI-apps
I'm not the site author, just submitting the link.
Not sure which part you need to be logged in to view - I'm seeing links to different articles and exercises and they are all visible without logging (I checked in an incognito window).