How to untar in different directory?

The default behaviour of (un-)tar is to extract everything at its original location. Sometimes, it is required to extract/restore to some other location (eg. for comparision or analysis before putting data back to original location). I found that default tar binary provided with Solaris does not provide any option to restore/untar in different location. Hence I needed to use GNU Tar (gtar) for this purpose. In following demo, I will show how to restore in different directory:

 Part 1: Creating a tar archive of a directory /tmp/A

# ls -la /tmp/A 
total 6
drwxr-xr-x   2 root     root         512 Jan 27 12:08 .
drwxrwxrwt  15 root     sys         1536 Jan 27 12:12 ..
-rw-r--r--   1 root     root           0 Jan 27 12:08 a
-rw-r--r--   1 root     root           0 Jan 27 12:08 b
-rw-r--r--   1 root     root           0 Jan 27 12:08 c

# tar cvf /dev/rmt/14 /tmp/A
a /tmp/A/ 0 tape blocks
a /tmp/A/a 0 tape blocks
a /tmp/A/b 0 tape blocks
a /tmp/A/c 0 tape blocks

# tar tvf /dev/rmt/14
drwxr-xr-x   0/0        0 Jan 27 12:08 2009 /tmp/A/
-rw-r--r--   0/0        0 Jan 27 12:08 2009 /tmp/A/a
-rw-r--r--   0/0        0 Jan 27 12:08 2009 /tmp/A/b
-rw-r--r--   0/0        0 Jan 27 12:08 2009 /tmp/A/c
===========================================================================
 Part 2: Extracting tar archive - to original location (i.e. /tmp/A) 

# tar xvf /dev/rmt/14
x /tmp/A, 0 bytes, 0 tape blocks
x /tmp/A/a, 0 bytes, 0 tape blocks
x /tmp/A/b, 0 bytes, 0 tape blocks
x /tmp/A/c, 0 bytes, 0 tape blocks


===========================================================================
 Part 3: Extracting tar archive - to Different location (i.e. /tmp/B) 
# gtar -C /tmp/B -xvf /dev/rmt/14 
/tmp/A/
gtar: Removing leading `/' from member names
/tmp/A/a
/tmp/A/b
/tmp/A/c


# ls -latrR /tmp/B
/tmp/B:
total 8
drwxrwxrwt  14 root     sys         1536 Jan 28 10:25 ..
drwxr-xr-x   3 root     root         512 Jan 28 10:26 .
drwxr-xr-x   3 root     root         512 Jan 28 10:26 tmp

/tmp/B/tmp:
total 6
drwxr-xr-x   2 root     root         512 Jan 27 12:08 A
drwxr-xr-x   3 root     root         512 Jan 28 10:26 ..
drwxr-xr-x   3 root     root         512 Jan 28 10:26 .

/tmp/B/tmp/A:
total 4
-rw-r--r--   1 root     root           0 Jan 27 12:08 a
-rw-r--r--   1 root     root           0 Jan 27 12:08 b
-rw-r--r--   1 root     root           0 Jan 27 12:08 c
drwxr-xr-x   2 root     root         512 Jan 27 12:08 .
drwxr-xr-x   3 root     root         512 Jan 28 10:26 ..

Note: gtar is located at /usr/sfw/bin/gtar in Solaris 9 and Solaris 10.

Resursive copy of data (with tar/untar method)

I used "cp -pr " method for many years to recusive copy of data from one source to another destination. But, recently I came across some drawbacks of this method and hence shifting to another method. :-)

The main disadvantage of copying bulk data was related to soft links. If the source data has any softlink that points to itself, then this command (cp -pr) can NOT be used. It will fill up the file system fast without complaining.

To overcome linked related problem, here is the new method I am using now:

date; cd /source_directory; tar cvf - * | ( cd /target_directory; tar xvfp -) ; date 

If I dont need verbose output, I can use following:

date; cd /source_directory; tar cf - * | ( cd /target_directory; tar xfp -) ; date