Also like the bootstrap.sh - very nicely structured and easier to verify than many others I've seen. I'd still prefer these scripts to output missing dependencies that calling sudo -- but otherwise very nice.

That is, rather than:

      function install_git() {
          echo 'Trying to install git'
          case $(uname -s) in
            #...
            Linux)
              if has_exec apt-get; then apt_update
                sudo apt-get install -y git
              #...
              else bail "Unknown linux variant"
              fi
              ;;
            *)
              bail "Unknown operating system $(uname -s)"
              ;;
          esac
      }

Simply aggreagate a list of missing packages, and ouput (based on a similar case-statement for detetining host):

    echo Please install missing packages:
    echo sudo apt-get install ${missing-deps}

https://github.com/larsyencken/marelle/blob/master/bootstrap...