Re: [gnubies-il] another reason to use tar
- stephen s fine wrote:
>A few useful remarks, IMO:
> On Sun, 28 May 2000, Alex Shnitman wrote:
> > > tar cspBf - . | (cd /mnt; tar xvvspBf -)
> > Any reason why not to use cp -a that I'm not aware of?
> in theory you have one process writing and one reading, so in an SMP
> machine, copying between two different partitions on two different
> drives on two different controllers, you could have a HUGE speed
> gain! :-)))
1. When taring special files like /dev files, dont forget to use the "p" option
to tar. Not doing so will result in a /dev directory with many, too many,
useless files and countless problems on your machine, from unusable printer to
non-existing mouse devices - all in one big surprise!... (more info on tar's
2. Not using the "--exclude" option of tar (or it's similar variants, AFAIK) can
result, like it resulted to me, in copying a nice file of the kernel image or
something, under the /proc dir'. This file was a few hundreds megabyte big... So
it is indeed preferred not to cause yourself such embarrassments, when you need
that server up, ASAP... :-) (even if your talking about a small home
3. There is another reason to use this sort of method to copy FS (tar vf - ... |
tar vf - ...):
The educational benefit. This is a common method of doing things on Unix.
Running one command and pouring it's output to a different command's standard
input via a pipeline, on the fly. One thing possible doing like that is to dump
complete disk on other empty disk. I cant recall the exact details but I
remember once I had to copy a SCSI disk and for some reason the only avail'
option was "dump -f - ...| restore -f - ..." . Learning and using it once
pushes into one's head that method of performing tasks on Unix.
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