# phpman > info > null

[NULL(4)](https://www.chedong.com/phpMan.php/man/NULL/4/markdown)                    Linux Programmer's Manual                   [NULL(4)](https://www.chedong.com/phpMan.php/man/NULL/4/markdown)

NAME
       null, zero - data sink

DESCRIPTION
       Data written to the /dev/null and /dev/zero special files is discarded.

       Reads  from  /dev/null always return end of file (i.e., [read(2)](https://www.chedong.com/phpMan.php/man/read/2/markdown) returns
       0), whereas reads from /dev/zero always return  bytes  containing  zero
       ('\0' characters).

       These devices 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 pro-
       grams will act strangely.

       Since Linux 2.6.31, reads from /dev/zero are interruptible by  signals.
       (This  change  was made to help with bad latencies for large reads from
       /dev/zero.)

SEE ALSO
       [chown(1)](https://www.chedong.com/phpMan.php/man/chown/1/markdown), [mknod(1)](https://www.chedong.com/phpMan.php/man/mknod/1/markdown), [full(4)](https://www.chedong.com/phpMan.php/man/full/4/markdown)

COLOPHON
       This page is part of release 5.10 of the Linux  man-pages  project.   A
       description  of  the project, information about reporting bugs, and the
       latest    version    of    this    page,    can     be     found     at
       <https://www.kernel.org/doc/man-pages/>.

Linux                             2015-07-23                           [NULL(4)](https://www.chedong.com/phpMan.php/man/NULL/4/markdown)