tar procedure may have been compamised

Posted on 2009-03-30
Last Modified: 2012-05-06
The cord on my laptop, got pulled out during the night (the cat :-(() and I am not sure if the tar file procedure finished or not. Other than restarting or completely untarring, is there a way I can ascertain whether this procedure completed?

Here is what I was using from OmarFarid:
from your laptop:

ssh username@remoteserver "tar cf - /path/to/dir" | dd of=/path/to/local/dir/mybackup.tar

Thanks in advance.

Question by:wotan1953
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LVL 68

Accepted Solution

woolmilkporc earned 250 total points
ID: 24018994
use 'tar -tvf /path/to/local/dir/mybackup.tar' to produce a table of contents.
If this works without error, the tarball should be OK.
LVL 40

Assisted Solution

omarfarid earned 250 total points
ID: 24019007

of the laptop run

dd if=/path/to/local/dir/mybackup.tar | tar xvf -

if you see an error or it does not show all files / folders then it is not complete.

Also, you could do

ssh username@remoteserver "du -ks /path/to/dir"

and compare its size with the tar file size


Author Closing Comment

ID: 31564324
Once again Thanks You. Although I split the points evenly, I liked  the tar (only) solution, better , there was a table with an 'OK' at the end. The dd solution actually created the directory structure. Both approaches worked, but upon using them I realized my scope narrowed. My error;-).  Thanks again for all your help.
LVL 40

Expert Comment

ID: 24019882
I am very sorry, it should have been tar -tvf -
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Author Comment

ID: 24019921
And I am adding another ... third times a charm :-))

Here is my run :

Title: Multiple ssh hops to tar to MAC laptop.


I need to ssh into server X and then ssh into server Y and tar up a dir (files and dirs), to my MAC laptop. I previously got this from OmarFarid:

ssh username@remoteserver "tar cf - /path/to/dir" | dd of=/path/to/local/dir/mybackup.tar.

I am thinking something like:

ssh username@remoteserver1 | ssh username@remoteserver2  "tar cf - /path/to/dir" | dd of=/path/to/local/dir/mybackup.tar

But not sure. Any help will be appreciated. If by some strange web of circumstances I am right, then the confirmation is still worth 500 pts. I am under the gun on this latest project, and I appreciated you folks help.

Thanks -

LVL 40

Expert Comment

ID: 24020064

ssh user@serverA "ssh user@serverB tar -cf - /path/to/dir" | dd of=/path/to/local/dir/mybackup.tar

Author Comment

ID: 24039583
Thanks ... quick followup on the this question "tar procedure may have been compamised", when U said run du -ks /path/to/dir, and compare the 2. I have had this come up again. They changed the network during th night , and I think another one of these, might have failed. When I run this du etc .. I get.

For the dir I was trying to tar:
username@remoteserver > du -ks rw/
870984  rw
username@remoteserver >

For the tarred file itself:
bash-3.2$ du -ks rw_sav_dir/
861640      solveint/

I guess my question is, "should these be exactly the same or close?"

When I run:
dd if=/path/to/local/dir/mybackup.tar | tar xvf -

there are no errors, but determining that all files/dirs are there is difficult, because the file structure is huge.

Any help will be appreciated.
LVL 40

Expert Comment

ID: 24042357
the results of both are in KB. The difference is 870984 - 861640 = 9344 KB which is about 9 MB which I think much. It could be that the tar did not complete successfully.

dd if=/path/to/local/dir/mybackup.tar | tar xvf -

results in restoring it to the local system and there you could do du -k again and compare the two results which could be close to each other or an exact match

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