Rich Gwilliam's digital shed
"File Transfer Protocol" is not exactly a skill; as the name suggests its a protocol used for sending files between servers. It's really widely used, although it was more essential before we started syncing files with GIT.
The "purest" way to use it is on the command line, but it's not the best. We're past the days of bulletin-board machines and FTP is now trivially wrapped in a useable layer by the likes of FTPZilla or CyberDuck; that's how I prefer to interact with it.
I've been using FTP since May 2012 (13 years).
Senior PHP Developer
For ASL I developed several long-lived and high volume telemetry systems. These processed large amounts of data and delivered it for rendering in charts and tables on a daily basis.
Full-stack Developer / Devops Engineer
At Hidden, I filled the role of an API Developer as well as a Devops Engineer. I updated and expanded existing legacy code to run on AWS Lambda functions for increased efficiency, and created Jenkins build servers for the Unity development team.