Bash runs on a lot more than Linux.

I ran a Docker container and copied a statically-linked curl and bash onto a scratch image and ran it, it does not work:

    $ docker run -it --rm  $(docker build -q .)
    /srvmon.sh: line 162: date: command not found

    $ cat Dockerfile
    FROM scratch
    COPY bash /usr/bin/bash
    COPY curl /usr/bin/curl
    COPY srvmon.sh /srvmon.sh
    CMD ["/usr/bin/bash", "/srvmon.sh"]

I'm not pointing this out to be pedantic. I'm pointing it out because there is a common misconception that all these things like "date" and "cat" and "mkdir" are part of Bash, but they're not, they're part of coreutils and there are dramatically different versions of coreutils on different installations of Linux, macOS, BSD, etc., and some environments (like barebones Docker containers) don't have coreutils at all.