1unsetopt [ {+|-}options | {+|-}o option name ] [ name ... ]
2                                       -
3       Unset  the  options for the shell.  All options specified either
4       with flags or by name are unset.  If no arguments are  supplied,
5       the names of all options currently unset are printed.  If the -m
6       flag is given the arguments are taken as patterns (which  should
7       be  quoted  to preserve them from being interpreted as glob pat-
8       terns), and all options with names matching these  patterns  are
9       unset.
10