Lint Dotenv Files For Duplicated Keys And Unsafe Formatting With Dotenv Linter

---
name: "Lint .env files for duplicated keys and unsafe formatting with dotenv-linter"
slug: "lint-dotenv-files-for-duplicated-keys-and-unsafe-formatting-with-dotenv-linter"
description: "Check dotenv files for duplicated keys, malformed values, and formatting mistakes before they break local runs or secret handoffs."
github_stars: 2068
verification: "security_reviewed"
source: "https://github.com/dotenv-linter/dotenv-linter"
author: "dotenv-linter"
publisher_type: "organization"
category: "Security & Verification"
framework: "Multi-Framework"
tool_ecosystem:
  github_repo: "dotenv-linter/dotenv-linter"
  github_stars: 2068
---

# Lint .env files for duplicated keys and unsafe formatting with dotenv-linter

Check dotenv files for duplicated keys, malformed values, and formatting mistakes before they break local runs or secret handoffs.

## Prerequisites

The dotenv-linter CLI or binary and a repository containing dotenv files to check.

## Installation

Requirements and caveats from upstream:
- [wemake-services/dotenv-linter](https://github.com/wemake-services/dotenv-linter) (Python)

Basic usage or getting-started notes:
- &nbsp;&nbsp;&nbsp;&nbsp;The <code>.env</code> file has a simple key-value format, for example: <code>FOO=BAR</code>.<br />
- ## 🚀 Usage
- $ dotenv-linter diff .env .env.example

- Source: https://github.com/dotenv-linter/dotenv-linter
- Extracted from upstream docs: https://raw.githubusercontent.com/dotenv-linter/dotenv-linter/HEAD/README.md

## Documentation

- https://dotenv-linter.readthedocs.io/

## Source

- [Agent Skill Exchange](https://agentskillexchange.com/skills/lint-dotenv-files-for-duplicated-keys-and-unsafe-formatting-with-dotenv-linter/)