[ILUG] tar

[Wesley Darlington]

On Mon, Oct 08, 2001 at 01:33:58PM +0100, Mark Kilmartin wrote:
> Is there any way to tell tar to output say <prefix>1.tar, <prefix>2.tar
> ... prefix<n>.tar
<snip>
> But I would rather a solution which would allow me to supply the prefix
> option and tar would then go and create as many 2G files as need to
> complete the backup.

This is just a thought, but if you call gnu tar like this...

    export TAPE=/tmp/thing.tar
    tar cv -M -L 512 -F ./rotate.pl what-to-backup ...
    ./rotate.pl  # Extra one necessary to rotate final file

...where /tmp/thing.tar is the base name of where you want the output to go, 
512 is the size (in kB) of each part file and ./rotate.pl is a script to do 
the rotating. Something like... [0]

------------------------------------------------------------------------
#!/usr/bin/perl -w
use strict;

my $filename = $ENV{TAPE};
my $i = 1;
my $worked = 0;

while (!$worked) {
    my $newfilename = sprintf ("%s.%04d", $filename, $i);
    ++$i && next if -e $newfilename;
    # <---- Race conditions `R' us
    rename ($filename => $newfilename) and $worked=1;
};
------------------------------------------------------------------------

Unrotating is a different problem. :-)

Wesley.

[0] Please, I just threw this together. :-)