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 permissions you specify are those which  are  to  be  allowed
       (not denied) to the users specified.
