Shameless plug: I've written books [1] which focuses entirely on the specific flavor supported by the tool or the programming language. I use plenty of examples

Shameless plug: I've written books [1] which focuses entirely on the specific flavor supported by the tool or the programming language. I use plenty of examples to present the features one by one. These can be used for learning purposes as well as handy reference guide. I think of regular expressions as a mini-programming language, and use loose fitting analogies Anchors --> adding if conditions Alternation --> Conditional OR a(b|c)d = abd|acd --> a(b+c)d = abd+acd Quantifiers --> string repetition and range operators Dot metacharacter + quantifiers + alternation --> Conditional AND Capture group and backreference --> variable Subexpression call --> function Character class --> sets Lookarounds --> custom conditionals Flags --> like command line options So far, I've written books for Ruby and Python regular expressions, and BRE/ERE/PCRE/Rust for "GNU grep and ripgrep". Currently writing a book for GNU sed. [1] https://learnbyexample.github.io/books/ https://learnbyexample.github.io/books/