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Beginner Topic 6 of 50 DevOps & Tooling

Environment Variables

Named values configuring processes.

How it works

Environment variables are named string values attached to a process and inherited by the processes it starts. They are set with export in a shell, with a .env file loaded by a tool, or by the container or service manager, and read through the language runtime, for example process.env or os.environ. Common ones include PATH, which lists directories searched for commands, HOME, USER and LANG. Changing a variable in a child process does not affect its parent. Shell startup files such as .bashrc and .profile set them for each session.

Where it is used

Applications use them to switch between development, staging and production, to pass database URLs, ports and feature settings, and to inject credentials without hard-coding them, as the twelve-factor approach recommends.

Common pitfall

Committing .env files with secrets, printing the environment into logs and assuming a variable is set cause leaks and crashes. Variables set in one terminal are not visible to a service or cron job. Validate required variables at startup and keep secrets in a secrets manager.

Where it fits in the course

Environment Variables is topic 6 of 50 in DevOps & Tooling, rated Beginner. It follows Package Managers. The next topic is Git Basics.

Practice and explore

How to study this topic

  1. Read the explanation above and restate the definition in your own words.
  2. Open the interactive lesson and answer its mini quiz.
  3. Read the common pitfall, then write a short example that avoids it.
  4. Check your understanding in the DevOps & Tooling quiz, and revisit the topic if you miss a question.

Frequently asked questions

What is Environment Variables?
Named values configuring processes. It belongs to DevOps & Tooling and is a beginner-level topic.
Where do people use Environment Variables?
Applications use them to switch between development, staging and production, to pass database URLs, ports and feature settings, and to inject credentials without hard-coding them, as the twelve-factor approach recommends.
What is the most common mistake with Environment Variables?
Committing .env files with secrets, printing the environment into logs and assuming a variable is set cause leaks and crashes.
What should I learn before this topic?
Start with Package Managers, the topic just before it in DevOps & Tooling.
How can I practice it?
Answer the mini quiz in the interactive lesson, then take the DevOps & Tooling quiz.
Is Environment Variables hard to learn?
It is a Beginner topic, so it works as an entry point. If the terms are new, read the explanation twice and try the visualizer before the quiz.
How long does it take to learn Environment Variables?
Most learners can read the explanation and finish the interactive lesson in under an hour. Fluency comes from applying the idea, so plan a few short practice sessions with the quiz.
Which topics are related to Environment Variables?
Package Managers, Git Basics, Text Editors and IDEs are closely connected. The full list is in the related topics section of this page.
What should I study after Environment Variables?
Continue with Git Basics, the next topic in DevOps & Tooling.

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