Python Spawn New Process SubProcess don't wait

Spawn New Process:
You can spawn a new process within an another process
You can make use of subprocess to start a new process

proc = Popen([python process_doc.py], shell=True, stdin=None, stdout=None, stderr=None, close_fds=True)

close_fds makes the parent process file handles inaccessible for the child

Once it hits Popen, it startes daemon process and coninues execution (parallely daemon process will coninue executing)

Example:
.....
print "Before Daemon Process to Start"
proc = Popen([python process_doc.py], shell=True, stdin=None, stdout=None, stderr=None, close_fds=True)
print "After Daemon Process to Start"

.....

In the above example, the parent process don't wait for child process (process_doc.py) to wait till it executes completely. It spawns new daemon process and continues.
This daemon process executes separately, finish the task and dies.

Run command in Shell:
cmd = 'python /tmp/test.py'
subprocess.call(cmd, shell=True) #Synchronous
subprocess.Popen(cmd, shell=True, executable='/bin/bash') #Asynchronous ****