Unknown option: "-4" Unix manual page for null. (host=minya system=Darwin) 
NULL(4)                  BSD Kernel Interfaces Manual                  NULL(4)

NAME
     null -- the null device

DESCRIPTION
     The null device accepts and reads data as any ordinary (and willing) file
     - but throws it away. The length of the null device is always zero.

FILES
     /dev/null

HISTORY
     A null device appeared in Version 7 AT&T UNIX.

BSD                              June 5, 1993                              BSD