# outil
[](https://hex.pm/packages/outil)
[](https://hexdocs.pm/outil/)
A library for writing command line tools. Like so:
```gleam
import gleam/erlang
import gleam/io
import gleam/list
import gleam/result
import gleam/string
import outil.{command, print_usage_and_exit}
import outil/arg
import outil/opt
fn say_hello(args) {
use cmd <- command("hello", "Say hello to someone", args)
use name, cmd <- arg.string(cmd, "name")
use enthusiasm, cmd <- opt.int(cmd, "enthusiasm", "How enthusiastic?", 1)
try name = name(cmd)
try enthusiasm = enthusiasm(cmd)
let message = "Hello, " <> name <> string.repeat("!", enthusiasm)
Ok(io.println(message))
}
pub fn main() {
let args =
// Erlang is not required, this example just uses it for getting ARGV
erlang.start_arguments()
// drop the program name from the arguments we pass in
|> list.drop(1)
say_hello(args)
|> result.map_error(print_usage_and_exit)
}
```
If you don't fancy this style of programming, check out [glint] or [Awesome Gleam] for alternatives.
Outil is not going to have many cool features for building comprehensive command line
interfaces. It is meant to fit simple programs with simple needs.
[glint]: https://github.com/tanklesxl/glint
[Awesome Gleam]: https://github.com/gleam-lang/awesome-gleam#cli
## Quick start
```sh
gleam run # Run the project
gleam test # Run the tests
gleam shell # Run an Erlang shell
```
## Installation
Outil is available on Hex and can be added to your Gleam project like so:
```sh
gleam add outil
```
and its documentation can be found at <https://hexdocs.pm/outil>.
## Changelog
### 0.3.1
* Added convenience helpers print_usage and print_usage_and_exit for handling command errors.
### 0.3.0
* Expanded the return type of commands to include a way for the command code itself to return errors.
* **BREAKING** Some types were renamed to support the above, and be more clear.
### 0.2.1
* Fixed some docs.
### 0.2.0
* **BREAKING** Simplified command implementation. The function is the command now, it no longer returns a `Command` value.
### 0.1.0
* Hello world!
* Something kind of working.
