Docker image error: "/bin/sh: 1: [python,: not found"

Question

I'm building a new Docker image based on the standard Ubuntu 14.04 image.

Here's my Dockerfile:

FROM ubuntu:14.04
RUN apt-get update -y
RUN apt-get install -y nginx git python-setuptools python-dev
RUN easy_install pip
ADD . /code
WORKDIR /code
RUN pip install -r requirements.txt # only 'django' for now
ENV projectname myproject
EXPOSE 80 8000
WORKDIR ${projectname}
CMD ['python', 'manage.py', 'runserver', '0.0.0.0:80']

When I try to run this image, I get this error...

/bin/sh: 1: [python,: not found

But if I open a shell when running the image, running python opens the interactive prompt as expected.

Why can't I invoke python through CMD in the Dockerfile?

@E-ebolavirus No, that's not the issue. Python is installed. I can invoke it just fine by changing the single quotes to double quotes. — Joe Mornin, Sep 22 '15 at 05:42

Aleksandr Kovalev · Accepted Answer · 2018-01-13T12:43:48.083

112

Use " instead of ' in CMD. (Documentation)

edited Jan 13 '18 at 12:43

answered Sep 22 '15 at 05:42

Aleksandr Kovalev

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`docker-compose build` is necessary too, after changing the file. – Niloct Jan 18 '17 at 12:56

score 20 · Answer 2 · edited Feb 21 '18 at 06:56

20

I have resolved my issue on my Mac by changing

CMD ["python", "app.py"]

to

CMD python app.py

edited Feb 21 '18 at 06:56

Pang

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answered Feb 15 '18 at 21:06

srinivasa karadi

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This answered worked for me, but I don't know why. Can anyone explain? According to docs, exec form is preferred so I'd prefer `["python", "app.py"]` if possible. – Ben Stickley Jul 27 '23 at 13:57

score 10 · Answer 3 · edited Nov 05 '20 at 02:51

10

I had the same error. But in my case it was syntax error in command.
I had a missing comma ","
CMD ["python" "app.py"]
instead of
CMD ["python", "app.py"]

Validating the yaml file format can help in this case. Can use any online yaml validator.

edited Nov 05 '20 at 02:51

cryanbhu

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answered May 26 '19 at 06:24

Apoorva Manjunath

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score 4 · Answer 4 · answered May 05 '20 at 10:08

I had similar issue, but I didn't have any ' or " chars in docker run command in my case. But I found the solution to repair that issue and maybe will help you in similar case in future:

Clear all unnecessary whitespace chars from Dockerfile
Clear all cached images from this Dockerfile
Build and run new image

If you don't clear cached images, docker will use cached image with some crazy whitespace chars, which was created the same error message like the subject of the thread.

score 1 · Answer 5 · answered Mar 10 '23 at 08:59

1

you must use " " doubleQoute for CMD ["python"]

answered Mar 10 '23 at 08:59

Fat3mi

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score 0 · Answer 6 · answered Aug 16 '22 at 09:33

Well, I had the same issue, all I had to do was to add a comma between the elements in your CMD array.

Most devs use visual studio code to write docker file and the official docker extension does not indicate an array if a comma is not added.

Also, use double quotes always.

Docker image error: "/bin/sh: 1: [python,: not found"

6 Answers6

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