Very Computer

I know they both compress files  into a main
file, but what is the advantage of one vs. the
other ??

TIA

--
The wealth of reality, cannot be seen from your locality.

I'm sure many others will post the actual list of differences between 'tar'
(Tape ARchiver) and 'cpio' (CoPy Input/Output).  I just wanted to point out
that neither does a compress!  Standard UNIX logic (not always agreed with)
is that each command should do a single job well.  Thus, 'tar' and 'cpio' can
create archives of files but 'compress' (or 'pack' or ...) is needed to
compress
them.   :-}
--

Gary Seubert
UNIX Class of '73 B.C. ('B'efore 'C'pio) [& before 'tar' for that matter!]

 short answer man cpio and man tar.

 cpio copies list of files; while tar can copy whole directories and subdirectories.

  richk

Quote:

>TIA

>--
>The wealth of reality, cannot be seen from your locality.

Quote:

>I know they both compress files  into a main
>file, but what is the advantage of one vs. the
>other ??

>TIA

Greetings,

This has long been a bone of contention for many system admins.
Which way to archive? 'tar' or 'cpio'.  I personally prefer
'cpio'. The 'tar' I am referencing below is not GNU 'tar',
which has more exteneded features and options.  A generic
'tar' vs generic 'cpio'.

tar                                     cpio
===                                     ====

Common to all UNIX flavors              Mostly for AT&Tish
                                        ,available on BSD systems.

Most of the tar's dont support          Writes multiple copies of
symbolic links                          links to tape

Can archive individual files            ditto

No multiple tape volumes                ditto

Backups are larger                      Backups are smaller, because of
                                        the smaller headers.

Read/write from a tape drive is         slower, the I/O block size is
faster, the max I/O block size is       5120 bytes.
10240 bytes.

Padding to even out block boundary      No padding.

Can not read or write device files      Can backup the file information
                                        but only headers. (Flames??)

Hierarchies can be a bottleneck, for    Filenames > 100 chars., is a problem.
the path length beyond 100 chars.,
is not easy to handle  

More portable                           Less portable.

Entire directory trees can be moved     Can be moved more easily with 'find'

Easy to use                             A little more tougher to use than
                                        'tar', but more options.
---------------------------------------------------------------------------------

I wish some more people contribute to this so I can post a summary.

Thanks

Ravi Kumar

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$I know they both compress files  into a main
$file, but what is the advantage of one vs. the
$other ??

   Actually, in most implementations, _neither_ one compresses.
They do _archive_ files together, but compression is a different
kettle of fish entirely.

   There are some compatibility issues with them, for example;
in many cases, cpio -c format is more likely to be portable
across dissimilar systems than cpio or tar format.  But as always,
there are exceptions, I'm quite sure.

   Also, some implementations of one command or another may suffer
from bugs or other problems.  For example, SCO's tar (at least
in 3.2v4.2 and below; I'm not sure about the present one) won't
back up neat things like device nodes.
--

----------------------------------------------------------------------------
Stephen M. Dunn, CNE, ACE, Sr. Systems Analyst, United System Solutions Inc.
104 Carnforth Road, Toronto, ON, Canada M4A 2K7          (416) 750-7946 x251

[snip]

Quote:

>    There are some compatibility issues with them, for example;
> in many cases, cpio -c format is more likely to be portable
> across dissimilar systems than cpio or tar format.  But as always,
> there are exceptions, I'm quite sure.

>    Also, some implementations of one command or another may suffer
> from bugs or other problems.  For example, SCO's tar (at least
> in 3.2v4.2 and below; I'm not sure about the present one) won't
> back up neat things like device nodes.

I haven't heard anyone mention what I consider the biggest reason *not* to
use tar (although I still do): Tar writes out one file whereas cpio copies
each file to the destination.  This means tar is more susceptible to bad
tape blocks than cpio is -- one bad block on the tar tape and you lose
your whole backup!

Regards,

Bret
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 Technical Director, WebNet Technologies      URL: http://www.wn.com
 Voice/FAX: 214.821.0848                      Pager: 214.816.0283
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Quote:>   Also, some implementations of one command or another may suffer
>from bugs or other problems.  For example, SCO's tar (at least
>in 3.2v4.2 and below; I'm not sure about the present one) won't
>back up neat things like device nodes.

Or symbolic links
--

Home page: http://www.texmicro.com/~max - (an exercise in egomania)
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