If you’re a developer: - SQL, this goes without saying but if you’re only using an ORM without knowing SQL, you’re setting yourself up for failure. - Regular

If you’re a developer: - SQL, this goes without saying but if you’re only using an ORM without knowing SQL, you’re setting yourself up for failure. - Regular expressions, it’s not that hard. Knowing how to read and write a regex without needing an external tool (I often use regex101 but I don’t need it) is a huge life saver. It also helps develop a good intuition of when to use (or not) a regex. - bash, a lot of people use it but never took the time to actually learn it (ie. can’t write a condition or a loop from the top of their head). You’ll use it your whole life, learn bash