Arch manual pages

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

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) 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 programs 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), mknod(1), full(4)

COLOPHON

This page is part of release 4.13 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/.
2015-07-23 Linux