Running executable from /opt/

General Discussions
1

I’m still a beginner, and not using Docker in the traditional way I guess. I’m trying to create an image for launching a processing engine (doesn’t really matter what it does here).

Here’s my Dockerfile:

FROM ubuntu:18.04

WORKDIR /app

COPY mypackage_23.0.1.2755-1_x64.deb ./

RUN bash -c 'apt update'
RUN bash -c 'apt -y install ./mypackage_23.0.1.2755-1_x64.deb'

# export some environment variables for licensing purposes
# and some settings irrelevant here

CMD ['/opt/mypackage/bin/myEngine']  # Launch a process that will run undefinitely

When running the image in a container, this is what I’m getting:
2023-09-06 16:51:16 /bin/sh: 1: [/opt/mypackage/bin/myEngine]: not found

Using Docker Desktop, I can check the file exists with the Files tab (see screenshot).

image
image408×662 15.5 KB

I also tried to add a symlink in /usr/bin and using the symlink:

# ...
RUN bash -c 'ln -s /opt/mypackage/bin/myEngine /usr/bin/myEngine'

CMD ['myEngine']

and this is the result:
2023-09-06 16:56:37 /bin/sh: 1: [myEngine]: not found

Once again, using the Files tab, I double checked the symlink existed, and targetted the correct path.

My question is: how can I run the executable using Dockerfile? Thanks

2

The problem is probably the content of myEngine. Make sure it has line breaks as Linux expects it. LF (line feed) and not CRLF (Carriage return + line feed) which is for Windows.

Is that file created by the deb package? If it is, who created that package?

Some other recommendations unrelated to your issue:

You probably don’t need bash to run apt update and it should be apt-get update in the same instruction where you run the install command.

RUN apt-get update \
 && apt-get install -y ./mypackage_23.0.1.2755-1_x64.deb

You need a bash shell only if you want to use features that works only in a bash shell. Regarding apt, as far as I know apt is still not stable and not recommended to run it in a script. Not to mention that you are using an old LTS :slight_smile: Again, this is not related to your original issue.

3

myEngine is a binary file. It is created by the .deb package, which is created by my company. As far as I know, everything is compiled on Ubuntu 18.04 LTS (thus why I’m using the same version), so I don’t think bad line ending applies.

Thanks for the tips, I’ll try them even if it doesn’t solve the main issue.

4

Okay, you were right. The issue is usually what I mentioned, but in this case after I tried, I realized the problem is that you are using single quotes. Try it with double quotes:

CMD ["/opt/mypackage/bin/myEngine"]

A little explanation: The syntax of the CMD is json and in json quotes are double quotes.

1 Like
5

Thanks, that was the issue!