At my previous workplace I spent 90% of my time writing server side .Net code, on Windows (no mono). At my current workplace I shifted to a linux only environment.
Linux is an old buddy, but It was always a fling, not a serious relationship.
It took me a while to adjust to working on linux every day, and finding out that now the terminal is my best friend, as opposed to GUI in windows.
linux command line basics series really helped me get started: part one, part two.