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.