There are four parts where I could see sys.path manipulation being mentioned while running scripts : 

-c option (https://docs.python.org/3/using/cmdline.html#cmdoption-c)
-m option (https://docs.python.org/3/using/cmdline.html#cmdoption-m)
-  (input option) 
<script> (running as script)

For some reason I am not able to hyperlink to - and <script> parts since they are not a command line option but a method to execute code. I could sys.path references in windows (https://docs.python.org/3/using/windows.html#finding-modules) where `._pth` file is mentioned to completely override sys.path. 

I am new to adding documentation so add in if it needs a simple reference or explain the option which I feel redundant and useful at the same time kind of missing the point of cross-referencing. I am attaching a patch for `-m` and <script> option. Feel free to add comments and if I am missing something.

Thanks