Passing string from python programs to external programs

[lone_eagle]

Hi all,

On Linux, I do something like this

$ program_to_execute < input_file
... get some output ...

I have the content of the input_file as a string inside a python
program and would like to pass this string to the external program
from inside the python program and get back the programs output in a
string/file. Can someone tell me how to achieve this. I have been
through the documentation for Popen, but this one beats me.

Cheers,
Chaitanya