topic Re: Reading from tar in Operating System - HP-UX

Reading from tar

Waqar Razi — Fri, 01 Aug 2008 15:25:20 GMT

I have an ignite backup tap and I wanna check if particular file is present on the tape, lets say for example /etc/passwd

I am issuing the following command.

tar -tvf /dev/rmt/0mn /etc/passwd

Instead of just listing passwd file, it lists the whole contents of the archive. How can I just check for a single file say /etc/passwd if it is present on archive or not?

Re: Reading from tar

Uday_S_Ankolekar — Fri, 01 Aug 2008 15:52:19 GMT

Did you use grep ?
tar -tvf ..... |grep filename

Re: Reading from tar

Patrick Wallek — Fri, 01 Aug 2008 16:00:19 GMT

Have a look at the tar man page.

The '-t' options lists the names of ALL files in the tar archive. The '-t' option does NOT accept a filename as an argument to list only one file.

So doing:

# tar -tvf /dev/rmt/0mn /etc/passwd

is exactly the same as doing:

# tar -tvf /dev/rmt/0mn

The '/etc/passwd' argument is ignored.

Re: Reading from tar

Dennis Handly — Fri, 01 Aug 2008 16:04:10 GMT

The -t option in tar will list ALL files, so you can pipe to grep.

pax(1) allows you to provide a pattern but it will probably read the whole tape.
pax -nv -f /dev/rmt/0mn etc/passwd
-n says it selects the first, so that might work.

Re: Reading from tar

Dennis Handly — Fri, 01 Aug 2008 17:13:36 GMT

>... provide a pattern

Make sure you get a listing of what you want to find so you can check your pattern. I.e. if it is a file matching pattern, or something like a regular expression where it isn't automatically anchored with ^ and $.

Re: Reading from tar

Rasheed Tamton — Sat, 02 Aug 2008 12:06:17 GMT

mt -t /dev/rmt/0mn fsf 1 ; tar -tvf /dev/rmt/0m /etc/passwd

Make sure to use the no-rewind device to position the tape with mt.

I am not sure may be filename cannot have a leading path, I can't check now.

tar -xvf /dev/rmt/0m etc/passwd

Make a copy of the current /etc/passwd file before you restore.

Re: Reading from tar

Deepak Kr — Sun, 03 Aug 2008 22:04:42 GMT

Hi Razi,

Please try using :

# tar -tvf /dev/rmt/0mn|grep "/etc/passwd"

regds,
Deepak

Re: Reading from tar

Sharma Sanjeev — Mon, 04 Aug 2008 06:06:22 GMT

Hi Razi

Check with

tar -tvf /dev/rmt/0mn etc/passwd

etc/passwd not /etc/passwd

Regards
Sanjeev