python | subprocess module| subprocess.Popen| run OS command using subprocess 

This video will explain about running OS command using subprocess module.
In this module, we are using subprocess.Popen.
The subprocess module allows you to spawn new processes, connect to their input/output/error pipes, and obtain their return codes. This module intends to replace several older modules and functions:
you can download code from my github link: github.com/happycodingforyou/...
class subprocess.Popen(args, bufsize=-1, executable=None, stdin=None, stdout=None, stderr=None, preexec_fn=None, close_fds=True, shell=False, cwd=None, env=None, universal_newlines=False, startupinfo=None, creationflags=0, restore_signals=True, start_new_session=False, pass_fds=(), *, encoding=None, errors=None)
If shell=True, on POSIX the executable argument specifies a replacement shell for the default /bin/sh.
Popen.wait(timeout=None) : Wait for child process to terminate.
Popen.returncode : A None value indicates that the process hasn’t terminated yet.
A negative value -N indicates that the child was terminated by signal N (POSIX only).