The default Arch Docker image doesn't have these installed.

Reproduction:

FROM archlinux/base

RUN pacman -Syu --noconfirm sudo make && \
    curl -Lo ruby-install-master.tar.gz https://github.com/postmodern/ruby-install/archive/master.tar.gz && \
    tar -xzvf ruby-install-master.tar.gz && \
    cd ruby-install-master && \
    make install && \
    pacman -Syu --noconfirm grep awk && \
    yes | ruby-install ruby