How do I select GCC version in nix-shell?

Question

I am requesting GCC 8, but I get GCC 7 instead.

$ nix-shell -p gcc8
[nix-shell:~]$ gcc --version
gcc (GCC) 7.3.0

What is going on?

Answer 1

Use nix run instead. It behaves better, and also has nicer progress indicator when downloading packages.

jdanek@nixos ~ % nix run -f channel:nixos-19.03 gcc8
[jdanek@nixos:~]$ gcc --version
gcc (GCC) 8.3.0