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Test installs in a clean Ubuntu sandbox

#ubuntu #testing #tutorial #docker

When you include installation guides in your tutorials or documentation, it's good practice to test the installation steps. But what if you already have the tool installed on your machine and don't want to uninstall it?

Here's a simple, elegant solution: use Docker to spin up a fresh Ubuntu environment in seconds, no changes to your existing setup required.

Note: This guide is written for Ubuntu. Windows and macOS are not covered here.

🛠️ Step 1: Install Docker (if not already installed)

Check whether docker is already installed on your system:

docker --version
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If docker is not yet installed on your Ubuntu system, install it with:

sudo apt update
sudo apt install docker.io -y
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Then start the Docker service:

sudo service docker start
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You can verify the installation:

docker --version
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You should see something like:

Docker version 26.1.3, build 26.1.3-0ubuntu1~20.04.1
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🧪 Step 2: Launch a fresh Ubuntu container

Now spin up a fresh Ubuntu 22.04 container with:

docker run -it ubuntu:22.04 bash
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What this does:

  • docker run – creates and runs a container
  • -it – makes it interactive (so you can use it like a shell)
  • ubuntu:22.04 – pulls the official Ubuntu image from Docker Hub
  • bash – starts a Bash shell inside the container

👉 You're now inside a clean Ubuntu environment, just like a fresh server install.

🧪 Step 3: Test installation steps

Let's test the installation of the curl tool.

Inside the container, try running:

curl --version
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You'll likely get:

bash: curl: command not found
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This is exactly what we want. Now you can follow your installation guide exactly as a new user would:

apt update
apt install curl -y
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Then verify again:

curl --version
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You should now see the installed version:

curl 7.88.1 (x86_64-pc-linux-gnu) libcurl/7.88.1 OpenSSL/3.0.2 ...
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🧹 Step 4: Exit and throw away the test environment

When you're done testing, simply type:

exit
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The container stops and disappears. Your real system remains unchanged, and you can spin up a new clean one anytime by running the same command:

docker run -it ubuntu:22.04 bash
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✨ Conclusion

Using Docker to simulate a clean Linux environment is one of the easiest ways to validate installation instructions without touching your real system. It’s quick, lightweight, and repeatable.

Note: I use ChatGPT to help me gather information and shape these posts, but I always test the commands myself and add my own insights to make them easier to understand. This blog is my personal record of what I learn as I go deeper into Linux. If it helps someone else too, even better!

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