To learn package creation let's create a new package that will provide a `hello_world` command for your shell. Package names may only contain lowercase letters and hyphens to separate words.
Always describe how your package works in the `README.md`. Also read more about [auto completion](http://fishshell.com/docs/current/commands.html#complete) and take care to provide it for your utilities when applicable.
Each function in your package must be declared in its own file. This is required by fish autoloading mechanism, which loads functions on demand, avoiding loading unused functions.
Bear in mind that fish lacks a private scope, so if you need to split your package into functions, consider prefixing private functions like this: `__hello_world.my_extra_function`, to avoid both name clashes and global namespace pollution.
If you want to be [notified](http://fishshell.com/docs/current/commands.html#emit) when your package loads, declare the following function in your `hello_world.fish`:
Use this event to modify the environment, load resources, autoload functions, etc. If your package does not export any functions, you can still use this event to add functionality to your package.
## Uninstall
Oh My Fish emits `uninstall_<pkg>` events before a package is removed via `omf remove <pkg>`. Subscribers can use the event to clean up custom resources, etc.
