- Shell
  - The command shell is the nucleus of the Midas system.
  - It is the piece of software that receives and reacts to text commands from the user or interoperating software.
  - Throughout the history of the Midas family, there have been numerous shells with various features, some welcomed and others despised.
  - For flexibility, NeXtMidas and X-Midas provide two basic shell operating modes:
    Interactive
      The Midas shell is explicitly entered. Further interaction is done within the shell.
    One-Shot
      Midas starts up, runs a single command, and then exits.
      It is not uncommon for the "single" command to be a full-scale application.