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Grep by example: Interactive guide
via jbranchaud@gmail.com
https://antonz.org/grep-by-example/
grep
grep is the ultimate text search tool available on virtually all Linux machines. While there are now better alternatives (such as ripgrep), you will still often find yourself on a server where grep is the only search tool available. So it's nice to have a working knowledge of it.
There is a mini book, a playground, and interactive examples of practical ways to use grep.