Show HN: Interactive exercises for Linux CLI text processing commands

Last month, I started learning a Python TUI framework called Textual. After working on a 4x4 board game, I made an interactive app to test your CLI text processing skills with 40 beginner to intermediate level exercises. The app is fairly basic in terms of features — only single input file, so no stdin data, multiple files, etc.

Most of the exercises in this app is based on my Computing from the Command Line ebook (https://learnbyexample.github.io/cli-computing/preface.html). I hope to improve the TUI app to support all the 200+ exercises sometime next year.