I've written on this before, but I have an extensive collection of "at" scripts. This started 25+ years ago when I dragged a PC tower running BSD to a friend's house, and their network differed from mine. So I wrote an @friend script which did a bunch of ifconfig foo.
Over time that's grown to an @foo script for every project I work on, every place I frequent that has some kind of specific setup. They are prefixed with an @ because that only rarely conflicts with anything, and tab-complete helps me remember the less frequently used ones.
The @project scripts setup the whole environment, alias the appropriate build tools and versions of those tools, prepare the correct IDE config if needed, drop me in the project's directory, etc. Some start a VPN connection because some of my clients only have git access over VPN etc.
Because I've worked on many things over many years, most of these scripts also output some "help" output so I can remember how shit works for a given project.
Edit: a word on aliases, I frequently alias tools like maven or ansible to include config files that are specific to that project. That way I can have a .m2 folder for every project that doesn't get polluted by other projects, I don't have to remember to tell ansible which inventory file to use, etc. I'm lazy and my memory is for shit.
Slightly related but mise, a tool you can use instead of eg make, has “on enter directory” hooks that can reconfigure your system quite a bit whenever you enter the project directory in the terminal. Initially I was horrified by this idea but I have to admit it’s been quite nice to enter into a directory and everything is set up just right, also for new people joining. It has built in version management of just about every command line tool you could imagine, so that an entire team can be on a consistent setup of Python, Node, Go, etc.
I see other people mentioning env and mise does this too, with additional support to add on extra env overrides with a dedicated file such as for example .mise.testing.toml config and running something like:
MISE_ENV=testing bun run test
(“testing” in this example can be whatever you like)
I'm stealing the top comment here because you probably know what I'm asking.
I've always wanted a linux directory hook that runs some action. Say I have a scripts dir filled with 10 different shells scripts. I could easily have a readme or something to remember what they all do.
What I want is some hook in a dir that every time I cd into that dir it runs the hook. Most of the time it would be a simple 'cat usage.txt' but sometimes it maybe 'source .venv/bin/activate'.
I know I can alias the the cd and the hook together but I don't want that.
Its intended use case is loading environment variables (you could use this to load your virtualenv), but it works by sourcing a script — and that script can be ‘cat usage.txt.’
Great tool.
If you use Emacs (and you should!), there’s a direnv mode. Emacs also has its own way to set configuration items within a directory (directory-local variables), and is smart enough to support two files, so that there can be one file checked into source control for all members of a project and another ignored for one’s personal config.
direnv does exactly what you describe (and a lot more) using flake.nix. cd into the directory and it automatically runs. I use it in every single project/repository to set environment variables and install project-specific dependencies locked to specific versions.
As other comments say, direnv does that, but honestly you should look into mise-en-place (mise) which is really great, and also includes a "mini-direnv"
Over time that's grown to an @foo script for every project I work on, every place I frequent that has some kind of specific setup. They are prefixed with an @ because that only rarely conflicts with anything, and tab-complete helps me remember the less frequently used ones.
The @project scripts setup the whole environment, alias the appropriate build tools and versions of those tools, prepare the correct IDE config if needed, drop me in the project's directory, etc. Some start a VPN connection because some of my clients only have git access over VPN etc.
Because I've worked on many things over many years, most of these scripts also output some "help" output so I can remember how shit works for a given project.
Here's an example:
Edit: a word on aliases, I frequently alias tools like maven or ansible to include config files that are specific to that project. That way I can have a .m2 folder for every project that doesn't get polluted by other projects, I don't have to remember to tell ansible which inventory file to use, etc. I'm lazy and my memory is for shit.