On 03/14/2016 11:29 AM, Rick Stevens wrote:
On 03/14/2016 10:23 AM, jd1008 wrote:
On 03/14/2016 11:17 AM, Rick Stevens wrote:
On 03/14/2016 10:11 AM, jd1008 wrote:
Hi all,
time dd if=/dev/sr0 of=Our_Group_Picnic.iso bs=64M skip=5888
conv=noerror,notrunc oflag=append
dd: ‘/dev/sr0’: cannot skip: Invalid argument
0+0 records in
0+0 records out
0 bytes (0 B) copied, 0.000301689 s, 0.0 kB/s
but
{3464-jd@localhost}$ time dd if=/dev/sr0 of=Our_Group_Picnic.iso
bs=64M
conv=noerror,notrunc
works just fine.
So why is it that skip des not work on optical media?
Skip works fine, but you must specify the units. "skip=5888" doesn't
tell dd how far to skip. E.g. "skip=5888c" would skip 5888 bytes. From
the man page:
N and BYTES may be followed by the following multiplicative
suffixes: c=1, w=2, b=512, kB =1000, K=1024, MB=1000*1000,
M=1024*1024, xM=M GB=1000*1000*1000, G=1024*1024*1024, and
so on for T, P, E, Z, Y.
I thought that bs=64M applies to all io for input and output, and skip.
I did not specify ibs= nor obs=, just bs=
I've rarely used "ibs" and "obs" separately, just "bs". That being said,
I've always used the suffix with "skip".
It may be that "bs" does not set "ibs", so a "skip=5888" wouldn't have
the size. Don't know that for a fact, but it's possible. Stranger things
have been known to happen.
Well, it is also doing it on regular files. To wit:
$ ls -l
total 13662104K
-rw-r--r-- 1 jd jd 5970991104 Mar 14 12:15 test
-rw-r--r-- 1 jd jd 8018991104 Mar 14 12:02 Our_Group_Picnic.iso
{3507-jd@localhost}$ time dd if=Our_Group_Picnic.iso of=test bs=2K
skip=2915523K conv=noerror,notrunc oflag=append
dd: ‘Our_Group_Picnic.iso’: cannot skip to specified offset
0+0 records in
0+0 records out
0 bytes (0 B) copied, 0.000263412 s, 0.0 kB/s
real 0m0.00s
user 0m0.00s
sys 0m0.00s
So .... What's with dd???
This is a new behavior as far as I know. I have been using it since bsd 2.X
and skip always worked.
Installed is package: coreutils-8.23-11.fc22.x86_64
--
users mailing list
users@xxxxxxxxxxxxxxxxxxxxxxx
To unsubscribe or change subscription options:
https://admin.fedoraproject.org/mailman/listinfo/users
Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct
Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Have a question? Ask away: http://ask.fedoraproject.org
