JavaScript

https://regexlearn.com/ is interactive to get you started.

Then try reading maybe the python regex docs for more detailed info. There are multiple flavors of regex as well, which makes it even more confusing (yay), but you'll eventually grok it enough to make it a part of your toolbox! I use simple regex frequently for search/replace (VScode or vim), and in the shell.

For more complex string parsing operations, there's often a faster/better method than regex, but it's really good to know.