These are three tools I've gotten cozy with over the last few months writing software that I use daily.
GitHub is a web-based Git repository hosting service.
I had a Github account before I started my job, but I had only committed to my own repositories. Collaborating with a team, creating pull requests, and fetching others' code was new to me. I had to learn more Git commands than I needed as an individual and understand our team's flow for merging and reviewing code.
Tmux is an app that acts as a virtual console, allowing multiple terminal windows.
Tmux allows me to detach from a session of coding at my work computer and pick right back up from anywhere. I can keep processes running in the background, set multiple sessions for different projects, and open multiple windows within a session to organize my files.
Vim is a text editor for Unix systems.
For those of us newbies to the development world that have been raised by the friendly text editor apps like Sublime and Atom, Vim is a different animal, but extremely powerful when you become versatile.
Not only can you find answers to almost any programming question from this massive forum, the surveys shed insight into the actual workflows, tools and languages used by fellow developers around the world.