use IO::Select;

open my $file, '<', 'tail'  or  die $!;
my $select = IO::Select->new( $file );
while (my @ready = $select->can_read ) {
    for my $fh (@ready) {
        while ( sysread $fh, my $buff, 100 ) {
            syswrite STDOUT, $buff;
        }
    }
}
close $file;