linux man page for null

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

NAME
       null, zero - data sink

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

       Reads  from the null special file always return end of file (i.e., read(2) returns 0), whereas reads from zero always return bytes contain-
       ing zero ( 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:root /dev/null /dev/zero

FILES
       /dev/null
       /dev/zero

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

SEE ALSO
       chown(1), mknod(1), full(4)

COLOPHON
       This page is part of release 3.27 of the Linux man-pages project.  A description of the project, and information about reporting bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2009-02-23								   NULL(4)