[Tutor] working intime on pipes

[Jan Kenin]

Hello,

I have command, that runs pretty long and outputs many lines, that I
would like to filter. I call the command with

p=subprocess.Popen( command, stdout=out )

p.wait()

If out were sys.stdout, all output would be printed to the screen, which
I dont want to.

If out were an object with a write( *args ) attribute, this is not
called by p. p just calls out.fileno() and all is written to out without
using the write attribute.

How can I work on the lines sent to out, _before_ p has finished?

Thanks for usefull advice!