Signed-off-by: maipbui <maibui@microsoft.com>
#### Why I did it
`subprocess.Popen()` and `subprocess.run()` is used with `shell=True`, which is very dangerous for shell injection.
`os` - not secure against maliciously constructed input and dangerous if used to evaluate dynamic content
#### How I did it
Replace `os` by `subprocess`, remove `shell=True`
Remove unused functions