redhat man page for zero

NULL(4) 						     Linux Programmer's Manual							   NULL(4)

NAME
       null, zero - data sink

DESCRIPTION
       Data written on a null or zero special file is discarded.

       Reads from the null special file always return end of file, whereas reads from zero always return  characters.

       null and zero are typically created by:

	      mknod -m 666 /dev/null c 1 3
	      mknod -m 666 /dev/zero c 1 5
	      chown root:mem /dev/null /dev/zero

NOTES
       If these devices are not writable and readable for all users, many programs will act strange.

FILES
       /dev/null
       /dev/zero

SEE ALSO
       chown(1), mknod(1)

Linux								    1992-11-21								   NULL(4)