added links to books on cli text processing tools

Author: learnbyexample

README.md

@@ -16,6 +16,8 @@ Free to read online versions:
 * [Ruby one-liners cookbook](https://learnbyexample.github.io/learn_ruby_oneliners/)
 * [Perl one-liners cookbook](https://learnbyexample.github.io/learn_perl_oneliners/)
 * [Practice Python Projects](https://learnbyexample.github.io/practice_python_projects/)
+* [Command line text processing with GNU Coreutils](https://learnbyexample.github.io/cli_text_processing_coreutils/) — work-in-progress
+* [Command line text processing with Rust tools](https://learnbyexample.github.io/cli_text_processing_rust/) — work-in-progress
 
 :information_source: :moneybag: You can buy PDF/EPUB versions from [Gumroad](https://learnbyexample.gumroad.com/) or [Leanpub](https://leanpub.com/u/learnbyexample)