I can write in C, C++, and now C#. I like using Perl and Python but often have to look things up. I use SQL and know the basics. I use mostly Linux (Ubuntu, Lubuntu, Antix). In my professional life, I do a lot of physical computing, controls, and data acquisition for HVAC systems.
C#, .NET Core, Perl, Python, SQL, still learning new things in C/C++.
projects and hacks
Lately, I've focused on C#. Specifically, I'm trying to understand the control flow through a web app with database connections. I did finally manage to build a test web app that writes to a MySQL database that I know where everything goes, for once.