Linux

It doesn't have to be a big baroque thing. When there's a dotfile I configure regularly, I move it to a Git repo and use stow to put it "back" into place with a symlink. On new machines, it isn't long before I try something that doesn't work or see the default shell prompt and go "oh yeah, I want my dotfiles", check out the repo, run a script that initializes a few things (some stuff is machine-specific so the script makes files for that stuff with helpful comments for me to remember the differences between login shells or whatever) and then I'm off to the races.

In my case, I use several different types of machines: Personal Linux desktop, personal low end Linux laptop, remote servers where I have sudo, work Mac, shared remote work servers where I don’t have sudo. I want my setup to be basically the same everywhere so that my muscle memory works, but there are some things that also need to be a bit different for each. Hence, a dot files manager that lets me run one command to keep my environment consistent in all those different targets. I use chezmoi + git for it nowadays.