Learning basic *nix commands like sed, awk, and grep has helped me so much. I still frequently google/manpage them, but I often find myself thinking "I can do this with X in just a few seconds!"
being medium-grade conversant in regular expressions is right up there, too. You might not need to do lookaheads, but if you can write a regex search in vscode that finds and replaces something across a hundred files correctly, you've just saved yourself a ton of tedious manual labor.