subgroup-expression

    Specifies one or more groups to be inserted into a second group
    (indicated by group-expression). A subgroup expression can be a
    group name, a wildcard expression, or a list of these separated by
    commas.

 group-expression

    Specifies the group into which subgroup-expression is to be
    inserted. A group expression can be a group name, a wildcard
    expression, or a list of these separated by commas.

 remark

    Specifies a character string to be logged in the history file
    with this command, usually used to explain why the command was
    entered. The remark is enclosed in quotation marks. If no remark
    was entered, a null remark ("") is logged.