use strict;
use warnings;
my $tempfile = "temp.txt";
my $origfile = "guestbook.txt";
my $prepend_text = "Stuff to prepend...\n";
open TEMP, ">$tempfile" or die "Can't create temp file. $!\n";
print TEMP $prepend_text;
open ORIG, "<$origfile" or die "Can't read guestbook file. $!\n";
while ( my $line = <ORIG> ) {
    print TEMP $line;
}
close ORIG;
close TEMP or die "Unable to close output file: $!\n";
rename $tempfile, $origfile;

##</code><code>##

use strict;
use warnings;
use Tie::File;
my $string = "Text to be prepended.\n";
my @array;
{
    my $obj = tie @array, 'Tie::File', "guestbook.txt" 
        or die "Can't open the guestbook file. $!\n";
    $obj->flock;
    unshift @array, $string;
    untie @array;
}