Grep
Away with grep! Use ripgrep!
Ripgrep is a tool that recursively searches your current directory for a regex pattern. This article provides a brief overview of ripgrep and why it is a good alternative to grep.
I used ack for some time for grepping source code, yet I moved on to ripgrep since it offers quite a bit more than grep and source-code-greps like The Silver Searcher. Plus it can mostly replace grep and is about 6 times faster (it’s written in Rust). I am still astonished when I get results instantly.