DEFINE /LIKE

        [SIC\]DEFINE Type Var1 [Var2 [...]] /LIKE VarLike
        [SIC\]DEFINE IMAGE Var1 File1 Key1 [...]] /LIKE VarLike
        [SIC\]DEFINE STRUCTURE Struct1 [Struct2 [...]] /LIKE StructLike

    The /LIKE option allows definition of Type REAL, LOGICAL, DOUBLE or  IN-
    TEGER  arrays  with dimensions identical to those of the (existing) Var-
    Like array. IMAGEs and TABLEs can also be defined in this way.  The  di-
    mension field must not be specified in such a case.

    /LIKE  can  also be used in structure context: the new structure will be
    filled with a tree identical to the StructLike one (which can be a HEAD-
    ER or an IMAGE). However, the %DATA area of Structures and Images is ig-
    nored in this process, and should be defined separately if needed.

    The /LIKE option is incompatible with DEFINE FUNCTION,  DEFINE  COMMAND,
    as well as DEFINE HEADER and DEFINE FITS.