hi guys

i have a problem with tar command

i use absolute path to make a backup

tar cvf backup /home/user

and when i try to restore backup it doesn't destroy my files
tar xvf backup

it makes a directory with the name of home in my current directory although i've heard if we use absolute path to make a backup when we want to restore files they will extract in the same absolute path

for example:

if i make a backup with absolute path with this command

tar cvf backup /home/user

i think when i want to restore the backup
backup will restore exactly in /home/user and destroy all user files
however when i tested that it only makes a directory with the name of home in my current directory !!

is that right ??


another example :
according to this example

for backing up, you use
[/backups]# tar -cvf backup /home/user
& then you restore using
[/backups]# tar -xvf backup
the files will be restored to /home & not /backups,
but my files restored exactly in /backup a new directory with the name of home

Yes. But here's how you specify output dir.

bu it did not happen when i restore a tar file which was made with absolute path it didn't destroy my files !

You probably need -C / when extracting.
That will extract any dirs/subdirs/content directly under /.

tar tvf filename.tar.gz

This should show entries like
your/path/backed/up

Without slash at the start of the line.

did you read my question ???

i want to know the meaning of absolute path in tar !!!

it was written in a book when i use absolute path to make a backup when i want to restore the backup all file will restore in the same absolute path

e.g
for backing up, i use
[/backups]# tar -cvf backup /home/user
& then i restore using
[/backups]# tar -xvf backup
the files will be restored to /home & not /backups,

bu it did not happen for me ! my question is why ???

when i restored backup with above command all files restored in /backup instead of /home/user !!!! why ??

Because GNUtar acts this way I guess... Extraction goes to current directory by default.

http://lowfatlinux.com/linux-tar.html

tar tvf filename.tar.gz will show you what path components are in the path.

-C specifies the directory to start with. So each entry in the tar tvf ... listing will be added to the path specified with -C.

Copy from man page(this way you can remove part of the path taking into the tar tvf output):
Please post tar tvf output (only a few lines is ok).

It's just that his source absolute path becomes relative in tar archive (for extraction), that's pretty much covers it.

http://docstore.mik.ua/orelly/unix/upt/ch20_10.htm

see here

One problem with most versions of tar : it can't change a file's pathname when restoring. Let's say that you put your home directory in an archive (tape or otherwise) with a command like this:

%

tar c /home/mike

What will these files be named when you restore them, either on your own system or on some other system? They will have exactly the same pathnames that they had originally. So if /home/mike already exists, it will be destroyed


Tarfiles should not normally be created with absolute pathnames, only
with relative pathnames. Do not type "tar c /path/name" to create a tar
archive, type "(cd /path/name; tar c .)" instead.

The book's name is "UNIX power tools". As you probably know, there are several versions of TAR. UNIX and GNU is not the same.

Plus,
By Jerry Peek, Tim O'Reilly & Mike Loukides; ISBN 1-56592-260-3, 1120 pages.
Second Edition Edition, August 1997.

Plus,
your URL also says:
Use GNU tar (on the CD-ROM). It can ignore the leading / as it extracts files.
You use GNU tar, don't you? If "/" in the beginning is removed, path becomes relative. It is then extracted into current dir by default and path in tar archive concatenates with current dir's path. Deal with it.

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You don't need "v" option here. Just "tf".

In the manpage for tar, see the "-P" (--absolute-names) option. You would need to have used that when creating the archive.

As above:
by default, gnu tar drops the leading '/' when creating an archive.
You can use tar tf ... to see this.
You then have the option of (default) restore into current dir, OR use a switch to specify where to anchor the restore.
Your choice.

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