Talk:dd (Unix)

Learn The DD Command External Reference

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improve text / examples

I just /dev/zero'ed some harddisks and i found out, that the blocksize has a great performance impact

With defautl bs: 15MB/s

With bs=100M: 65MB/s

Maybe also mention that sending SIGUSR1 to gnu dd will make it print progress and writing speed.

Example code:

while sleep 1s; do killall dd -USR1 2> /dev/null; done &

dd if=/dev/zero of=/dev/hdb bs=100M

X/Open Portability Guide

WRT "In 1987, the dd command is specified in the X/Open Portability Guide issue 2 of 1987. This is inherited by IEEE Std 1003.1-2008 (POSIX), which is part of the Single UNIX Specification."

What does "this" refer to? the X/Open Portability Guide issue 2? Was that guide inherited into POSIX.1-2008? I find no evidence of that. Need a citation or to remove this claim.

Also, as this is history and the info is mostly chronological, it seems odd that a section about 1987 refers to something from 2008. Stevebroshar (talk) 14:33, 20 April 2025 (UTC)

A warning on disk-wipe examples?

"To write zeros to a disk, use dd if=/dev/zero of=/dev/sda bs=16M."

I agree that a normal reader with some basic understanding of linux and/or computer hardware will see the "Disk wipe" section title and understand the destructive capabilities of the command. But, as Wikipedia is targeting a much wider audience than that, I think it might be appropriate for us to...

1) "Warn" it with texts describing the commands' destructive capabilities, ideally somewhere close. _{e.g. "as overwriting disk's content with [other] data results in complete data lost, it is common for dd to be used for..."}

2) Warn it with explicit statements to the effect of "don't do this". _{I don't think this fits Wikipedia's MOS.}

3) Not state the commands at all, and just state dd's competency / usage as a data wiping tool. _{If the reader really wanted to do it, the answer is just one Google search away; and whatever ends up top in the results would hopefully have ample warnings.} 海盐沙冰 _{/ aka irisChronomia / Talk} 15:55, 23 September 2025 (UTC)