unsetopt [ {+|-}options | {+|-}o option_name ] [ name ... ]
       Unset  the  options for the shell.  All options specified either
       with flags or by name are unset.  If no arguments are  supplied,
       the names of all options currently unset are printed.  If the -m
       flag is given the arguments are taken as patterns (which  should
       be  quoted  to preserve them from being interpreted as glob pat-
       terns), and all options with names matching these  patterns  are
       unset.
