When a command is launched

                                                | `0' set to contain the
            |-----------------------------------| line exactly as typed
. <command> <thing1> <thing2> ... <thingk>
      |         |        |           |      |
      |         |        |           |      +--> `<k+1>' set to contain ""
      |         |        |           |                   (nothing)
      |         |        |           |
      |         |        |           +--> `<k>' set to contain "<thingk>"
      |         |        |
      |         |        |
      |         |        +--> `2' set to contain "<thing2>"
      |         |
      |         +--> `1' set to contain "<thing1>"
      |        |----------------------------------------------------|
      |                                |
      |                                |
      |          `*' set to contain "<thing> <thing2> ... <thingk>"
      |
      +--> Stata executes -<command>.ado-