File not found in docker container

Question

I'm doing something extremely simple. Here is my Dockerfile:

FROM alpine:latest

ADD hello.sh /bin/hello
RUN chmod +x /bin/hello

CMD /bin/hello

Then I build the image:

docker build -t hello .

Then I run the image:

docker run hello

And here is the output:

/bin/sh: /bin/hello: not found

Why is this happening? If I run:

docker run hello cat /bin/hello

I can see the content of my script, which makes me even more confused.

Answer 1

In my case the problem was that the line-endings for the script were Windows encoded instead of Linux. (Note: This was actually caused by git automatically converting them, which I disabled)

The first line of the script provides the file path to the shell. Because of the extra \r that is included with Windows EOL the system was trying attaching that hidden character to the filename and that's what caused the Not Found error.