www.LinuxHowtos.org

NULL

Section: Linux Programmer's Manual (4)
Updated: 2015-07-23
Index Return to Main Contents

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 (aq\0aq 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.)

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/.