EXPLAIN

        [VECTOR\]EXPLAIN [Task [Parameter]]

    Gives explanation about  a  GILDAS  task.  If  Parameter  is  specified,
    EXPLAIN will give help about the parameter. Parameter = * can be used to
    list help about all parameters of  the  specified  task.  Note  that  if
    Parameter is absent, EXPLAIN accesses the topic "Summary".

    The GILDAS tasks can only be activated from the VECTOR\  language,  with
    commands  RUN  or  SUBMIT.  The VECTOR\ language is included in programs
    VECTOR, GRAPHIC and other reduction programs such as MAPPING.

    From within RUN and SUBMIT commands, you can get help upon  the  current
    Task  by  typing  GOLD ? in the editor, or by answering ? to a prompt in
    non editing mode.