Python: How do I capture "cooked mode" / cbreak output of subprocess? -

what i'm trying do: i'm attempting write wrapper in python modifies output of openbsd command-line program before displayed user. command-line program interactive, , it's execution indefinite, wrapper has able modify output in "realtime" produced program. user running wrapper has able interact command-line program.

the problem i'm having: script works far, except when command-line program goes cooked-mode (cbreak). user able interact, program output shown, , string replace works. but, when child/subprocess in cooked mode, no output @ all. type not shown, until end of script execution, on exit, dumps @ once. non-cooked mode output shows after type in cooked-mode, , cooked-mode info still cached until end.

what have far: have far wrapper:

#!/usr/local/bin/python  import subprocess  process = subprocess.popen(['./cooked.pl'], stdout=subprocess.pipe)  while true:         output = process.stdout.readline()         if output == '' , process.poll() not none: break         if output:                 str.replace(output,"[3]","---");                 print output.strip()  rc = process.poll() print "done.\n" 

the actual program run older (1990) one; 1 referenced in script above drop-in substitution testing, written in perl. here source perl test script (cooked.pl):

#!/usr/bin/perl use strict; use term::readkey;  $key;  readmode 3; # cooked mode {         while (not defined($key=readkey(-1))) {                 # no keypress         }         print "[3] got key $key\n"; } while($key ne "q");      readmode 0; # reset tty mode before exiting 

my question summarized: need way wrap command-line program such can modify output before shown user, while allowing command-line program run indefinitely , allowing interaction. attempting python subprocess, running issues when command-line program in cooked-mode / cbreak; no output shown @ during cooked-mode on command-line program side.

thanks in advance help. open doing in language possibly. cannot make changes command-line program used in final script.