if haverubyversion, err := exec.Command("/var/lib/arvados/bin/ruby", "-v").CombinedOutput(); err == nil && bytes.HasPrefix(haverubyversion, []byte("ruby "+rubyversion)) {
logger.Print("ruby " + rubyversion + " already installed")
} else {
err = inst.runBash(`
tmp="$(mktemp -d)"
trap 'rm -r "${tmp}"' ERR EXIT
if haverubyversion, err := exec.Command("/var/lib/arvados/bin/ruby", "-v").CombinedOutput(); err == nil && bytes.HasPrefix(haverubyversion, []byte("ruby "+rubyversion)) {
logger.Print("ruby " + rubyversion + " already installed")
} else {
err = inst.runBash(`
tmp="$(mktemp -d)"
trap 'rm -r "${tmp}"' ERR EXIT