umask [ -S ] [ mask ]
       The umask is set to mask.  mask can  be  either  an
       octal  number  or  a symbolic value as described in
       chmod(1).  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 permissions you specify are those
       which  are  to be allowed (not denied) to the users
       specified.
