Since Dockerfile is a rather limited and (IMHO) poorly executed re-implementation of a shell script, why not use shell directly? Not even bash with coreutils is necessary: even posix sh with busybox can do much more than Dockerfile, and you can use something else (like Python) and take it very far indeed.
https://github.com/containers/buildah/blob/main/examples/lig...
Since Dockerfile is a rather limited and (IMHO) poorly executed re-implementation of a shell script, why not use shell directly? Not even bash with coreutils is necessary: even posix sh with busybox can do much more than Dockerfile, and you can use something else (like Python) and take it very far indeed.