#!/usr/bin/perl
 # Written by Michael Howe, in a desparate attempt to get tar to backup a 63GB
 # partition onto a filesystem that has a maximum size of 4GB.
 # Usage:
 #   Change $filename and $dir to the base filename (ie without .tar) and
 #   directory of the tar files.
 #   Then, use tar:
 #   tar -cvvM -L4194200 -F /path/to/this/script.pl -f /path/to/tar/file.tar /dir/to/tar
 #   tar will create 'file.tar', then when it gets to just under 4G, will call
 #   this script, which will move file.tar to file.00.tar, and start again on
 #   file.tar.
 #   Upon completion of the tar command, move file.tar to be the last in the
 #   series (ie file.01.tar (if the only other file is file.00.tar)).
 #
 # IMPORTANT:
 #   This may well eat your data, and could also fry your hardware, or (worst
 #   case) lead to an alien invasion.  I claim no responsibility - use at your
 #   own risk (and remember to backup).
 use strict;
 use warnings;
 use File::Copy;
 
 my $filename = "src";
 my $dir = "/tmp/tartest";
 
 my $latest = `ls -1 $dir/$filename.*.tar 2>/dev/null| sort | tail -1`;
 
 my $newname;
 print "Latest: $latest\n";
 if ( $latest ) {
 	my ( $number ) = $latest =~ m{.*\.(\d+)\.tar};
 	$number++;
 	print "Number: $number\n";
 	$newname = sprintf( "%s/%s.%02d.tar", $dir, $filename, $number );
 	( -f $newname ) && die "File $newname exists - script screwed!";
 } else {
 	$newname = "$dir/$filename.00.tar";
 }
 
 
 move( "$dir/$filename.tar", $newname );
 ( -f $newname ) and exit 0;