import signal
signal.signal(signal.SIGINT, signal.SIG_IGN)

import subprocess
cat = subprocess.Popen(['cat'])
subprocess.call(['gdb', '--pid=%d' % cat.pid])

import subprocess
cat = subprocess.Popen(['cat'])

import signal, os
signal.signal(signal.SIGINT,
              lambda signum, frame: os.kill(cat.pid, signum))

subprocess.call(['gdb', '--pid=%d' % cat.pid])