Comment by inshadows

It's nice but you cannot comment individual lines. For that you can go one step further and use arrays:

  cmd=(
    command
    -x -y
    --bar OPTARG
    ARG ARG
  )
  $cmd

This works in Zsh. In Bash that would be ${cmd[@]} I think. I use this with long qemu command lines where I often modify and comment out arguments during testing.