'netcat -e' not relaying stdout

I'm using netcat to create a backdoor running a python script with the following command: netcat -l -p 1234 -e 'python /script.py' then I'm connecting to the backdoor with another shell using: netcat localhost 1234 script.py is a simple loop that reads input, saves it to a file, and then prints it back. Now whatever I write in the second shell goes to the script and is successfully saved to a file. However, I don't see the output of the script on the second shell. I tried both the print and sys.stdout.write methods of python and both seem to fail. I don't know why the output is relayed back to the second shell if I use this: netcat localhost 1234 /bin/bash But not with my script. I'm obviously missing something important. Here is my script: import sys while 1: kbInput = sys.stdin.readline() sys.stdout.write( 'Input: '+kbInput) f = open("output.txt", "w") f.write(kbInput) f.close() print