$buffer->set_text($sysbuffer);
Gtk2->main_iteration while Gtk2->events_pending;
[download]

Here is a pretty good complete scrolled textview example to help you out. (A commented out IO::Pipe method works too)

#!/usr/bin/perl -w
use strict;
use Glib  qw(TRUE FALSE);
use Gtk2 -init;
use Gtk2::Helper;

#use IO::Pipe;
#open a pipe to a command
#my $fh = new IO::Pipe;
#$fh->reader("top -b");
#$fh->reader("counter1.pl");

#open(FH, "counter1.pl |") or die "$!\n";
open(FH, "top -b |") or die "$!\n";

#add a watch to this file handle
my $helper_tag = Gtk2::Helper->add_watch(fileno FH, 'in',sub{
            &watch_callback('FH');
        });

#standard window creation, placement, and signal connecting
my $window = Gtk2::Window->new('toplevel');
$window->signal_connect('delete_event' => sub { exit;});
$window->set_border_width(5);
$window->set_position('center_always');

my $hbox = Gtk2::HBox->new();
$hbox->set( "border_width" => 0 );
$window->add($hbox);

my $scroll   = Gtk2::ScrolledWindow->new;
$scroll->set_size_request(600,600);
my $textview = Gtk2::TextView->new;
my $buffer = $textview->get_buffer;
create_tags($buffer);

$scroll->add($textview);
$hbox->pack_start($scroll,1, 1, 1 ); # expand?, fill?, padding;

$window->show_all();

#our main event-loop
Gtk2->main;

sub watch_callback {

    my ($fh) = @_;
    
    my $line;
    #read 1000 caracters of the buffer
    #$fh->sysread($line,1000);
    sysread(FH,$line,1000);
      
    #remove the newline
#    print $line;
    chomp $line;
    
    if($line){
           $buffer->insert_with_tags_by_name($buffer->get_end_iter, $l
+ine,'blue');
    }else{
           Gtk2::Helper->remove_watch($helper_tag);                 
    }

        
    #absolutely need the main iteration here, or you
    #won't get the end iter correctly 
        Gtk2->main_iteration while Gtk2->events_pending;
        $textview->scroll_to_iter($buffer->get_end_iter,0,0,0,0);

#        my $end_mark = $buffer->create_mark( 'end', $buffer->get_end_
+iter, FALSE );
#        $textview->scroll_to_mark( $end_mark, 0.0, FALSE, 0.0, 1.0 );


    #important so we can loop again    
    return 1;
}
###########################################3
sub create_tags{
  my $buffer = shift; 

   $buffer->create_tag('blue',
           foreground => 'blue',
           );

   $buffer->create_tag('col',
           foreground => 'green',
       );

}
#########################################
__END__
[download]

Not sure what exactly you mean by "slow and fragmented" (I haven't run your program), but if it's updating in about 1 sec intervals, you could try to reduce the sleep interval of tail, for example to 0.1 sec

-s, --sleep-interval=S
    with -f, sleep for approximately S seconds (default 1.0) between i
+terations.
[download]

Just an idea.

Your code has too much in it, for me to run. I need to get Linux::CDROM, setup a bunch of directories, run as root, etc. If you want answers to questions, make the simplest possible script that demonstrates the problem. That way people can run it, and easily see the glitch. Usually when you do this simplification, you will answer your own question. This script just has too much clutter for me to make sense out of.

I think my problem is in the fact that everytime new data is in the filehandle, the buffer is overwritten. Is there a way to append data to the end of the buffer as it comes in?

Well, you are overwriting it with set_text. You can make a global variable, that you append to

my $buftext ='';
.....
$buftext .= $sysbuffer;
$buffer->set_text($buftext);

# or better.....insert at the end_iter

$buffer->insert( $buffer->get_end_iter, $sysbuffer );
[download]

The end_mark and end_iter concepts are hard to get right, it's best to make a few simple examples for yourself to play with them.

Also, if you read the warning messages, you should change 'add' to 'add_with_viewport' at the lines specified; it will make the scrollbars work better.

---

I'm not really a human, but I play one on earth. Cogito ergo sum a bum

Thank you, that change works like a charm. Your help is much appreciated!