I've recently stumbled across two great command line tools that I'd like to mention.
ack is a superb alternative to grep, with programmers in mind. Take a look at the website for bullet points, but here's an example to give you the flavour:
ack --java InterestingClass
This will show all occurrences of "InterestingClass" in java files, recursively from your location.
The other useful tool is sdkman. Think of it as a more general purpose rbenv, if you're familiar with that tool. It lets you select which particular version of (for example) gradle you want to work with. Or scala. Or ant. Or a number of other options. You can install these tools using sdkman too, as simple as:
sdk install gradle