How to Start a Stopped Docker Container with a Different Command

TLDR

You can't directly change the command of a stopped Docker container when restarting it with docker start. Instead, create a new container from the same image with a different command or entrypoint. Use docker run --entrypoint or docker commit for advanced cases.

Why Can't You Change the Command with docker start?

When you create a container with docker run, the command and entrypoint are set at creation. docker start always uses the original command, so you can't override it for an existing container.

Option 1: Create a New Container with a Different Command

The most reliable way is to start a new container from the same image, specifying the new command:

docker run -it my-image /bin/bash

Or, to override the entrypoint:

docker run -it --entrypoint /bin/sh my-image

This gives you a fresh container with your chosen command.

Option 2: Use docker commit to Save Changes (Advanced)

If you need to preserve changes made in the stopped container (like files or installed packages), you can commit it to a new image:

docker commit my-container my-temp-image

Then run a new container from that image with a different command:

docker run -it my-temp-image /bin/bash

Option 3: Use docker exec for Running Containers

If the container is running, you can start a new process inside it:

docker exec -it my-container /bin/bash

But this doesn't work if the container is stopped.

Best Practices

• Use docker run with a new command for most cases.
• Use docker commit only if you need to preserve changes from the stopped container.
• For debugging, override the entrypoint or command as needed.
• Clean up old containers and images to avoid clutter.

Conclusion

You can't change the command of a stopped Docker container when restarting it, but you can create a new container from the same image (or a committed image) with any command you need. This gives you flexibility for debugging, recovery, or running alternate workflows.

Related Resources

• Docker Run vs Docker Start: understand the difference
• How to Run a Command on an Existing Container: exec into containers
• Why Docker Container Exits Immediately: debug exit issues
• Introduction to Docker Guide: Docker fundamentals