Usage:

    unset <variable-name>

 'unset' causes the specified variable to _have_no_value_.  This means that
 it will not be used by archie until it has been given a value with the 'set'
 command.


 Note: this may cause "counter-intuitive" behaviour in some cases (e.g. in
       the case of "maxhits").  Although one might expect 'prog' to print
       matches without regard for any limit, this is not the case.  If the
       value of "maxhits" is not available it will merely fall back to some
       internal default.