No ouput until program end, why?

I am running a PHP program under Linux on the command line. The problem I have is that I get no output to the screen until the program finishes. I have lots of echo statements throughout the program to help me debug but none of them are printed until the program finishes, which is really a pain since the prog takes 30 minutes to run ... The main() looks something like this. Can someone help me figure out why it is not printing anything until the program exists? pg_exec($CONN, "BEGIN"); for ($i = 0; $i < 6001; $i++) { $retval = process($aFields); if ( ($i % 100) == 0 ) echo "$i\n"; if ($retval == 1) echo "error on line $i \n"; } echo "COMMIT \n"; pg_exec($CONN, "COMMIT"); Thanks, Jc