The tar command questions

[ajk_5]

Hi all,

I would like to know how I can view a specific file in a backup tape quickly using tar?

Also, How can I know how many bytes I did backup all files in the tape?

Thanks very much!

Best Regards
ajk

[Massimo Bianchi]

Hello,
what do you mean by "quicly" ?
As far as i know, there is no fast way , you can only use a "tar -tvf FILENAME" to list the content of the tar.

Tar has no funzionality like index in fbackup.

If you plan it, you can create an index file each time you create a tape, using

tar -cvf ARCHIVE FILES | tee -a /INDEXDIR/ARCHIVE.index

but this can only be usefull for the future.

HTH,
Massimo

[Michael Tully]

$ tar tvf myarchive /directory/filename
This will give the permissions/owner/bytes/date etc

To get the total you would have to write a small awk script to get total of the column of bytes.
$ tar tvf mayarchive >/tmp/archive.out

Regards
Michael
"When I have trouble spelling, it's called fat finger syndrome"

[Michael Tully]

Here's a simple way to get the total number of bytes.

$ tar tvf myarchive >/tmp/wrk

$ cat /tmp/wrk | awk '{t1+=$3}
>END {printf("Total %d\n",t1)}'

Regards
Michael
"When I have trouble spelling, it's called fat finger syndrome"

[Leif Halvarsson_2]

Hi,
As you can see, tar is not very useful as a general backup program. Perhaps you should look at fbackup or better, Data Protector or some other high end product.

[RAC_1]

tar -tvf tar_archive > /tmp/list.txt

Check list.txt.

No fast way here.

[Jean-Louis Phelix]

hi,

Concerning the view of a specific file, managing an index could be ok.

But to check the amount of data in a tar file, dd could be even faster ...

For example :

> ll /tmp/a
-rw-rw-rw- 1 phelix CST 26767360 May 21 10:59 /tmp/a.tar
> dd if=/tmp/a.tar of=/dev/null bs=1024k
25+1 records in
25+1 records out

Which means that you have 26*1024k plus one incomplete record (less than 1024k) in the file.

Regards.

[V. V. Ravi Kumar_1]

Hi,
if ur using /dev/rmt/0m tape device, to view a file the only way is
# tar tvf /dev/rmt/0m

To know howmany bytes, redirect the tvf output to a file.
# tar tvf /dev/rmt/0m >/tmp/tar.lst
Write a small script
x=0
for i in `cat /tmp/tar.lst|awk '{print $3}'`
do
x=`expr $x + $i`
done
echo $x

[John Meissner]

This proceedure will pull off a gzip'd tar file of the tape. you can then look at it in a normal tar -tvf

cd /var/tmp
dd ibs=10k if=/dev/rmt/0m of=archive.gz