#!/usr/bin/env perl
use 5.010; use strict; use warnings;

my $l;               # chunk of a line
my $tiny_buffer = 8; # tiny buffer for testing

while( read DATA, $l, $tiny_buffer ){
    for (split ' ', $l){
        if( $_ eq '0' ){
            say 'Reached the end';
            exit;
        }
        say "; $_ ;";  # do stuff with the digit
    }
}

__DATA__
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 0