EXPLAIN

        [VECTOR\]EXPLAIN [Task [Parameter]]

    Gives  explanation  about  a GILDAS task. If Parameter is specified, EX-
    PLAIN will give help about the parameter. Parameter = * can be  used  to
    list  help  about all parameters of the specified task. Note that if Pa-
    rameter 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.