svn commit: r187923 - stable/7/bin/dd

Giorgos Keramidas keramida at
Fri Jan 30 08:28:35 PST 2009

Author: keramida (doc committer)
Date: Fri Jan 30 16:28:32 2009
New Revision: 187923

  MFC 187922,187609 from /head
    Add an example of using bs=2048 to duplicate data CD-ROMs.
    This should be a bit useful for users who look at the manpage and
    then try to copy data CD-ROM disks using dd.  A lot of us know
    that bs=2048 is required, but it still manages to cause a bit of
    grief to those who haven't heard about it.
    PR:             bin/130857
    Submitted by:   Tri Brotoharsono < mail at >

  stable/7/bin/dd/   (props changed)

Modified: stable/7/bin/dd/dd.1
--- stable/7/bin/dd/dd.1	Fri Jan 30 16:23:57 2009	(r187922)
+++ stable/7/bin/dd/dd.1	Fri Jan 30 16:28:32 2009	(r187923)
@@ -32,7 +32,7 @@
 .\"     @(#)dd.1	8.2 (Berkeley) 1/13/94
 .\" $FreeBSD$
-.Dd August 15, 2004
+.Dd January 23, 2009
 .Dt DD 1
@@ -392,6 +392,11 @@ Remove parity bit from a file:
 Check for (even) parity errors on a file:
 .Dl "dd if=file conv=pareven | cmp -x - file"
+To create an image of a Mode-1 CD-ROM, which is a commonly used format
+for data CD-ROM disks, use a block size of 2048 bytes:
+.Dl "dd if=/dev/acd0 of=filename.iso bs=2048"
 .Xr cp 1 ,
 .Xr mt 1 ,

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