read() or readline() clobbers my variable

[washu]

Hi,

This may be a simple problem but I can't seem to find a way around it. 
I've pasted my code snippet below:

import os

input = os.popen("echo hello")
input.readline()
input.readline()

The first input.readline() gives the output.  The second readline() gives
an empty line.  It almost seems like input acts as a buffer which gets
emptied when you read it.

I even tried setting it equal to another variable (temp = input) but it
seems like temp receives a pointer that just points to input. 
temp.readline() produces the same results.

I'd like to basically freeze the contents of input for further
manipulation or comparison.  Any ideas?