open(FH,">","$post_data_file");

$ofh = select(FH); $| = 1; select ($ofh);

while (read (STDIN ,$LINE, 4096) && $b_read < $len )
{
    if (-e "$exit_file") { unlink ("$exit_file"); exit;}

    $b_read += length $LINE;
    
    select(undef, undef, undef,0.01);
    
    print FH $LINE;
}