1null(4)                    Kernel Interfaces Manual                    null(4)
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NAME

6       null, zero - data sink
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DESCRIPTION

9       Data written to the /dev/null and /dev/zero special files is discarded.
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11       Reads  from  /dev/null always return end of file (i.e., read(2) returns
12       0), whereas reads from /dev/zero always return  bytes  containing  zero
13       ('\0' characters).
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15       These devices are typically created by:
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17           mknod -m 666 /dev/null c 1 3
18           mknod -m 666 /dev/zero c 1 5
19           chown root:root /dev/null /dev/zero
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FILES

22       /dev/null
23       /dev/zero
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NOTES

26       If these devices are not writable and readable for all users, many pro‐
27       grams will act strangely.
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29       Since Linux 2.6.31, reads from /dev/zero are interruptible by  signals.
30       (This  change  was made to help with bad latencies for large reads from
31       /dev/zero.)
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SEE ALSO

34       chown(1), mknod(1), full(4)
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38Linux man-pages 6.05              2023-02-05                           null(4)