Stack Overflow Developers Survey
Stack Overflow is a community of nearly 5 million developers who ask and answer programming questions, if I ever have questions about programming or scripting it is the first site I look to for answers.
They also run an annual survey looking at current trends within the developer community, the results probably represent the most comprehensive survey of it's type. The results make interesting reading and I'd certainly suggest that you go an look at the results in details, but I've pulled out a couple of interesting points.
JavaScript is the most commonly used programming language, but that is probably because the web is now the most popular front-end to applications and services. If you look at the developers involved in Math and Data the profile is rather different with Python now the dominant language.
The most loved programming languages are Rust and Swift, and the most dreaded Visual Basic, interestingly none of which appear in the most used technologies.
Among the desktop operating systems MacOSX is increasingly popular rising from 18% in 2013, largely at the expense of Windows.