bs

An environment manager for your shell.

Usage

Place a .env file in your project with the environment variables you need.

For instance:

$ cat .env
RACK_ENV=development
REDIS_URL=redis://127.0.0.1:6380

Then:

$ bs rackup -p 8080

This will run rackup with your environment variables set.

If you want to drop to a new shell to work for a little while, just:

$ bs

To restore the old environment, simply Ctrl-D and go back to the parent shell.

Sometimes you’ll want to modify the environment of your current shell without creating a new one (for instance, if your init scripts modify the environment and overwrite what bs is setting for you). That’s easy to do:

$ source bs

Or the more cryptic:

$ . bs

Motivation

We are long-time users of gs. This small tool allows you to start a shell (or run a command) within a specific gem set. And it does it beautifully simply: by only setting a few environment variables which RubyGems will honor. That’s it.

Then there’s Foreman. We use it to read our Procfile and start our services. But it also has the feature of loading a .env file and setting environment variables before spawning your processes.

Now Foreman is a gem, so it should be installed inside the application’s gem set. So, what if you need to run irb inside a bare shell?

$ gs foreman run irb

We realized we could replace gs by setting the appropriate variables in our .env file:

GEM_HOME=$(pwd)/.gs
GEM_PATH=$(pwd)/.gs:$(gem env path)
PATH=$(pwd)/.gs/bin:$PATH

Now we had everything in our .env file and foreman start would pick it up. But there are a few problems:

  1. We don’t use Foreman in production (at least not yet), so our deploy scripts needed a simple way to also read .env without needing the whole of Foreman.

  2. Foreman itself is a gem, so you would need to install it in your global gem set.

  3. Some people don’t use Foreman at all.

We needed something simple, probably pure-shell, to read .env and either run a given command or drop to a new shell with the variables set (similar to how bash or sh behave).

Installation

Place bin/bs somewhere in your $PATH.

With Homebrew:

$ brew tap educabilia/tooling
$ brew install bs

Support

All of the features are tested on Bash and Zsh. We’ll happily take patches to make bs POSIX-compliant.

Acknowledgements