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| -rw-r--r-- | man4/null.4 | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/man4/null.4 b/man4/null.4 new file mode 100644 index 0000000..c1299fb --- /dev/null +++ b/man4/null.4 @@ -0,0 +1,52 @@ +.\" Copyright (c) 1993 Michael Haardt (michael@moria.de), +.\" Fri Apr 2 11:32:09 MET DST 1993 +.\" +.\" SPDX-License-Identifier: GPL-2.0-or-later +.\" +.\" Modified Sat Jul 24 17:00:12 1993 by Rik Faith (faith@cs.unc.edu) +.TH null 4 2023-02-05 "Linux man-pages 6.05.01" +.SH NAME +null, zero \- data sink +.SH DESCRIPTION +Data written to the +.I /dev/null +and +.I /dev/zero +special files is discarded. +.PP +Reads from +.I /dev/null +always return end of file (i.e., +.BR read (2) +returns 0), whereas reads from +.I /dev/zero +always return bytes containing zero (\[aq]\e0\[aq] characters). +.PP +These devices are typically created by: +.PP +.in +4n +.EX +mknod \-m 666 /dev/null c 1 3 +mknod \-m 666 /dev/zero c 1 5 +chown root:root /dev/null /dev/zero +.EE +.in +.SH FILES +.I /dev/null +.br +.I /dev/zero +.SH NOTES +If these devices are not writable and readable for all users, many +programs will act strangely. +.PP +Since Linux 2.6.31, +.\" commit 2b83868723d090078ac0e2120e06a1cc94dbaef0 +reads from +.I /dev/zero +are interruptible by signals. +(This change was made to help with bad latencies for large reads from +.IR /dev/zero .) +.SH SEE ALSO +.BR chown (1), +.BR mknod (1), +.BR full (4) |