unsetopt [ {+|-}options | {+|-}o option name ] [ name  ...
]

       Unset   the   options  for  the shell.  All options
       with flags or by name are unset.  If  no  arguments
       the names of all options currently unset are print-
       flag is given the arguments are taken  as  patterns
(which  should

       be  quoted  to preserve them from being interpreted
       terns), and all options with names  matching  these
       unset.
