Why is “docker start” outputting the name of the container?

I have a small minimal test container made using the ruby image. The ruby script is simple, and outputs the single string “Twitter”.

When I first run the image and create the container, I get this output:

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  • $ docker run -it --name my-running-script my-ruby-app
    Twitter
    

    Great so far – the script completes and the container exits.

    But when I try to start it again, it first outputs the name of the container:

    $ docker start -a my-running-script
    my-running-script
    Twitter
    

    What is causing this output, and how can I get it to stop? (It’s printed on stdout, and redirecting stderr doesn’t help.)

    I don’t know if it’s relevant, but this is running on OS X using boot2docker.

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  • One Solution collect form web for “Why is “docker start” outputting the name of the container?”

    This is the expected behavior for docker start. Then you can do things like assign the containerID to a variable, etc.

    Docker will be the best open platform for developers and sysadmins to build, ship, and run distributed applications.