Dependency rules describe the relationships  among  the  files  in  a
    software system and specify the actions MMS is to perform in updating
    those files.

    Format:

      target,... : source,...  [! comment]
              action line    [! comment]

    Targets and sources  are  OpenVMS  file  specifications  or  mnemonic
    names.   A  target  is the file you want updated.  A source is a file
    from which the target is built and can be optional.  You must begin a
    target/source  line  in column 1 of the line, and you must include at
    least one space or tab on each side  of  the  colon.   A  comment  is
    simply a string of text that documents the description file.

    An action line contains a CLI command that specifies how  the  target
    is  to  be built from the source.  An action line must be indented by
    at least one space or tab below the corresponding target/source line.
    When  you  run  MMS,  all  action  lines,  including any comments you
    specified in the description file, are written to SYS$OUTPUT  (or  to
    the file specified by the /OUTPUT qualifier) as they are executed.

    MMS supplies some default, or "built-in," dependency rules.  You  can
    also define your own rules.