Projects I work on wind up with a bin/ directory containing any number of little helper scripts and tools. With direnv that dir can automatically be first in yo

Projects I work on wind up with a bin/ directory containing any number of little helper scripts and tools. With direnv that dir can automatically be first in your PATH when you're in the project, but not on it at all when you're elsewhere. Ditto for, say, putting a Python project's virtualenv/bin folder on PATH or a NodeJS project's node_modules/.bin. Projects I'm on also tend to wind up with an etc/ directory that configures things like PATH and tab completions for a good baseline experience - think of it as standardizing and isolating the snippets many projects tell you to put in your ~/.bashrc to work on the project. Direnv makes it easy to automatically load those, too. It really did revolutionize the way I work, by making it trivial to make projects much more self-contained, the way I'd always wanted them to be but hadn't been quite sure how to achieve. I've only used Nix for managing my personal installed package on OS X so far, but I believe direnv works really well in tandem with Nix - use a Nix file to define your project's dependencies and use direnv to automatically activate all those dependencies whenever you're in the project's directory.