Bash. It has enabled me to automatize a lot of sh*t I wouldn’t do just because it would take me a lot of time/efford to do. There’s a LOT you can do with a few simple scripts, a few examples:
…you name it…
…in most cases just by typing one word in the terminal. It was kind of a mindblow coming from the crappy window$ crappysystem eons ago.
Good F#$%^ riddance.