At LinkedIn everyone had a Linux desktop that matched the server environment. Very few people actually coded on their desktop though. Most of us used a MacBook then either tested on the desktop or tested on a dev server.

At Google, almost everyone used a MacBook or their Goobuntu desktop (Google’s custom version of Ubuntu). Basically everyone would remote into their desktop to write code. Some people used Windows and some used Chromebooks.

At Facebook, most used MacBooks, the rest were pretty evenly divided between Windows and Linux (on Thinkpads). Everyone had a Linux dev server in one of the data centers to test on.

At every one of these places, the production environment is 100% Linux, so eventually, everyone had to test their code on Linux (except mobile or desktop app developers).