umask [ -S ] [ mask ]
       The umask is set to mask.  mask can be either an octal number  or  a
       symbolic  value  as  described in the chmod(1) man page.  If mask is
       omitted, the current value is printed.  The  -S  option  causes  the
       mask  to  be  printed  as  a symbolic value.  Otherwise, the mask is
       printed as an octal number.  Note that in the symbolic form the per-
       missions you specify are those which are to be allowed (not  denied)
       to the users specified.
