I have a python script that basically runs forever and checks a webpage every second and notifies me if any value changes. I placed it on an AWS EC2 instance and ran it through ssh. The script was running fine when I checked after half an hour or so after I started it. 
The problem is that after a few hours when I checked again, the ssh had closed. When I logged back in, there was no program running. I checked all running processes and nothing was running. 
Can anyone teach me how to make it run forever (or until I stop it) on AWS EC2 instances? Thanks a lot. 

Edit: I used the Java SSH Client provided by AWS to run the script
You can run the program using the nohup command, so that even when the SSH session closes your program continues running.
Eg: nohup python yourscriptname.py &
For more info you can check the man page for it using
man nohup.
Make python script to run forever on Amazon EC2