The simplest way would be to just clear screen and set the cursor to top-left before each redraw:

 print "\x1b[2J\x1b[0;0H";  # erase screen, set cursor to top left
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See also Term::Screen, Curses and lots of other stuff you can find on cpan searching for ANSI. and Term.

#! /usr/bin/perl -w
#
# file:    banner-1.pl
# purpose: try to write a scrolling banner
# details: this script shows how to implement a scrolling banner
#   that will run in a xterm window.
#
# author:  chad c d clark
# created: 2006-05-21
#
# based on the following code by Chris Angell:
#   perl -e'$|++; 1 while select("","","",.04), 
#           print "\b", qw(/ - \ |)[$i++%4]'
#
# $Id$

use strict;
use POSIX;  # ceil()

# my $MESG = "This is my test message.  ";
# my $SIZE = 70;
# #my $SIZE = 10;

# my $MESG = " " . `/usr/bin/w | /usr/bin/sed 2d`; chomp $MESG;
# my $SIZE = 70;

my $MESG = qq{
The reason I'm so excited is it looks like if you plot price against
profit, you get a nice curve with a big hump in the middle! And we all
+ know
what humps mean! Humps mean local maxima! Or camels. But here they mea
+n
local maxima! - Joel Spolsky
};
my $SIZE = 70;

$|++;  # do not buffer output I/O

# remove "non-printable" characters (for example newlines)
if ($MESG =~ s/[^[:print:]]/ /g) {
    print STDERR "$0: Warning removing non-printable characters from m
+essage.\n";
}

my $offset = 0;             # start at beginning of the message
my $length = length $MESG;  # get the length of the message

# to simulate a circular buffer the idea is to append the message stri
+ng
# to itself until we have enough extra to cover the display window.
my $mult = ceil( ($length + $SIZE) / $length );
$MESG = $MESG x $mult;

print "Text:  ";
# prime the loop for the space where the message will be printed
print " " x $SIZE;

while (1) {

    # get a chunk of the message
    my $chunk = substr $MESG, $offset, $SIZE;

    # print the chunk over the the last iteration
    print "\b" x $SIZE, $chunk;

    select("","","",.15);  # sleep for part of a second

    # advance/wrap the offset pointer
    if (++$offset >= $length) { $offset = 0 };
}

exit(0);
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The main difference to your approach is that it sets up the entire image as an array of lines instead of printing every character as it comes along. This is done by the sub image(). It uses the core module Time::HiRes to set the frame rate with sub-second resolution. The "@" is moved through a sample of six positions and back again.

use Time::HiRes qw( sleep);

use constant SIZE => 15;

my @map = do {
    my @ones = ( 1) x SIZE;
    my @mixed = ( 1, ( 0) x (SIZE - 2), 1);
    (
        [ @ones],
        map( [ @mixed], 1 .. SIZE - 2),
        [ @ones],
    );
};

my @positions = ( [ 8, 4], [ 9, 5], [ 10, 6], [10, 7], [10, 8], [ 10, 
+9]);

my $clear_string = `clear`;
for my $pos ( @positions, reverse @positions ) {
    print $clear_string;
    print image( \ @map, @$pos);
    sleep 0.2;
}
exit;

sub image {
    my ( $map, $x, $y) = @_;
    my @image = map join( '', map $_ ? '* ' : '  ', @$_), @$map;
    $_ .= "\n" for @image;
    substr( $image[ $y], 2*$x, 1) = '@';
    @image;
}
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