NULL
Section: Linux Programmer's Manual (4)
Updated: 2015-07-23
Page Index
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
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