If you are a developer, you should use some sort of time tracking, especially when you are a freelancer. Tracking your time can help you improve your workflow and calculate realistic proposals.
If you work a lot in the BaSh, you will appreciate the ability to create own preferences and shortcuts. Those will make the terminal an even more powerful tool.
I don't know how I survived before knowing Sublime Text. For me, there is no better editor. It's slim, fast and incredibly adaptable. Not at least because of the thousands of packages available. These ones are my favorites
