python program linux background running

linux semaphore

• SIGINT
  • Ctrl + C sends sigint semaphore
• SIGHUP
  • Close session to send sighup semaphore

start command

program

test.py

# encoding=utf8
import time
if __name__ == "__main__":
    i = 0
    while True:
        print i
        time.sleep(1)

• python test.py &

  • output to terminal
  • Receive SIGHUP semaphore to kill process
  • Does not respond to SIGINT semaphore

• nohup python test.py

  • output to nohup.out
  • Receiving a SIGINT semaphore kills the process
  • Does not respond to SIGHUP semaphores

• nohup python test.py &

  • no output
  • Does not respond to SIGHUP semaphores
  • Does not respond to SIGINT semaphore
  • End the process with the kill command