As my Docker container starts up, I need to run this line:

cp /lib/libc.musl-x86_64.so.1 /lib/ld-linux-x86-64.so.2

Both of these files only exist in the Docker container after some packages have been installed.

In the Dockerfile, I have tried:

RUN cp /lib/libc.musl-x86_64.so.1 /lib/ld-linux-x86-64.so.2

COPY /lib/libc.musl-x86_64.so.1 /lib/ld-linux-x86-64.so.2

ENTRYPOINT ["cp","/lib/libc.musl-x86_64.so.1 /lib/ld-linux-x86-64.so.2"]

And also created a bash script that contains (among other things) this line. I know the script has run as the other changes it makes are present, but the file is not copied.

#!/bin/sh

apk add build-base
apk add libc6-compat

cp /lib/libc.musl-x86_64.so.1 /lib/ld-linux-x86-64.so.2

Then run with

RUN ./my_bash_script.sh

However, when I use the command line in the Docker container, and run the line manually, it works.

Why are the Dockerfile commands not copying this file?

Edit: My complete Dockerfile

FROM golang:alpine
ENV APP_NAME hello-world
ADD env_setup.sh .
RUN chmod +x env_setup.sh
RUN ./env_setup.sh
WORKDIR /home/helloworld
ADD vendor/ ./vendor/
COPY main.go .
COPY go.mod .