⚡️Lightning-fast linter for .env files. Written in Rust 🦀
`dotenv-linter` can **[check](#-check)** / **[fix](#-fix)** / **[compare](#-compare)** `.env` files for problems that may cause the application to malfunction.
**Available checks**:
✅ Duplicated Key
✅ Ending Blank Line
✅ Extra Blank Line
✅ Incorrect delimiter
✅ Key without value
✅ Leading character
✅ Lowercase key
✅ Quote character
✅ Space character
✅ Substitution Key
✅ Trailing whitespace
✅ Unordered Key
**What is a `.env` file?**
💡 A .env file or dotenv file is a simple text file containing all the environment variables of a project.
Storing configuration in the environment variables is one of the tenets of the Manifesto of Twelve-Factor App.
The .env file has a simple key-value format, for example: FOO=BAR.
More information you can find in articles in English and Russian.
**The key features**:
⚡️ Lightning-fast because it is written in Rust 🦀
💣 Can be used on any project regardless of the programming language 💥
🚀 Can be integrated with reviewdog and other CI services (including GitHub Actions and Super-Linter) 🔥
**Articles about dotenv-linter**:
- [EN] [Dotenv-linter: looking after the environment for you](https://evrone.com/dotenv-linter)
- [EN] [What's new in dotenv-linter v2.2.0?](https://evrone.com/dotenv-linter-v220)
- [EN] [What are the key changes in dotenv-linter v3.0.0 release?](https://evrone.com/dotenv-linter-v300)
- [RU] [Dotenv-linter: линтер .env файлов](https://www.mgrachev.com/2020/04/20/dotenv-linter)
- [RU] [Что нового в dotenv-linter v2.2.1?](https://evrone.ru/dotenv-linter-v220)
- [RU] [Что нового в dotenv-linter v3.0.0?](https://evrone.ru/dotenv-linter-v300)
## 👨💻 Installation
### Pre-compiled binary
```shell script
# Linux / macOS / Windows (MINGW and etc). Installs it into ./bin/ by default
$ curl -sSfL https://raw.githubusercontent.com/dotenv-linter/dotenv-linter/master/install.sh | sh -s
# Or a shorter way
$ curl -sSfL https://git.io/JLbXn | sh -s
# Specify installation directory and version
$ curl -sSfL https://git.io/JLbXn | sh -s -- -b usr/local/bin v2.0.0
# Alpine Linux (using wget)
$ wget -q -O - https://git.io/JLbXn | sh -s
```
You can find other installation methods here: https://dotenv-linter.github.io/#/installation
## 🚀 Usage
#### ✅ Check
By default, `dotenv-linter` checks all `.env` files in the current directory:
```shell
$ dotenv-linter
Checking .env
.env:2 DuplicatedKey: The FOO key is duplicated
.env:3 UnorderedKey: The BAR key should go before the FOO key
Checking .env.test
.env.test:1 LeadingCharacter: Invalid leading character detected
Found 3 problems
```
#### 🛠 Fix
It can also fix the found warnings with the `fix` command:
```shell
$ dotenv-linter fix
Fixing .env
Original file was backed up to: ".env_1601378896"
.env:2 DuplicatedKey: The BAR key is duplicated
.env:3 LowercaseKey: The foo key should be in uppercase
All warnings are fixed. Total: 2
```
#### 🤲 Compare
In addition, `dotenv-linter` can compare `.env` files with each other and output the difference between them:
```shell
$ dotenv-linter compare .env .env.example
Comparing .env
Comparing .env.example
.env is missing keys: BAR
.env.example is missing keys: FOO
```
Other use cases you can find on the documentation site (https://dotenv-linter.github.io):
- [Check](https://dotenv-linter.github.io/#/usage/check)
- [Fix](https://dotenv-linter.github.io/#/usage/fix)
- [Compare](https://dotenv-linter.github.io/#/usage/compare)
## 🚦 Continuous Integration
`dotenv-linter` can also be used with CI services such as: [GitHub Actions](https://dotenv-linter.github.io/#/integrations/github_actions) and [Circle CI](https://dotenv-linter.github.io/#/integrations/circleci).
## 🚧 Benchmark
Benchmarking [dotenv-linter/dotenv-linter](https://github.com/dotenv-linter/dotenv-linter) and [wemake-services/dotenv-linter](https://github.com/wemake-services/dotenv-linter) has done using the [hyperfine](https://github.com/sharkdp/hyperfine) utility:
| Command | Mean [ms] | Min [ms] | Max [ms] | Relative |
| :----------------------------------- | -----------: | -------: | -------: | ------------: |
| `dotenv-linter/dotenv-linter .env` | 2.7 ± 0.4 | 2.0 | 4.3 | 1.00 |
| `wemake-services/dotenv-linter .env` | 162.6 ± 12.1 | 153.0 | 201.3 | 60.83 ± 10.20 |
Content of .env file used for benchmarking
```dotenv
SPACED=
KEY = VALUE
SECRET="my value"
SECRET=Already defined
kebab-case-name=1
snake_case_name=2
```
## ✌️ Mentorship
`dotenv-linter` is not just a linter for `.env` files — it is also a **contributor-friendly open-source project** with the purpose of helping others learn Rust using a simple, but useful tool. 😊
In addition to studying Rust, this project has another goal — to **promote love for open-source**, help you with the first steps in it and give an opportunity to contribute to the open-source project written in Rust. ❤️
We act [as a mentor](https://rustbeginners.github.io/awesome-rust-mentors) within this project and **help developers** follow the path of a novice contributor from start to the top. 🤗
## 🤝 Contributing
If you've ever wanted to contribute to open source, now you have a great opportunity:
- [How to set up the project](/CONTRIBUTING.md#how-to-set-up-the-project)
- [How to add a new check](/CONTRIBUTING.md#how-to-add-a-new-check)
## 👍 Similar projects
- [wemake-services/dotenv-linter](https://github.com/wemake-services/dotenv-linter) (Python)
## ✨ Contributors
This project exists thanks to all the people who contribute. [[Contribute](/CONTRIBUTING.md)].
## ♥️ Sponsors
[dotenv-linter](https://evrone.com/dotenv-linter?utm_source=github&utm_campaign=dotenv-linter) is created & supported by [Evrone](https://evrone.com/?utm_source=github&utm_campaign=dotenv-linter). What else we develop with [Rust](https://evrone.com/rust?utm_source=github&utm_campaign=dotenv-linter).
Become a financial contributor and help us sustain our community.
## 📃 License
[MIT](https://choosealicense.com/licenses/mit)