call program to view file after post

maybe this already exists, but I can’t find it?

I’d love there to be an application option to set a path to an application (in my case Notepad++) such that whenever I post a new code it automatically opens it in the specified program(application path) where I can inspect and/or edit it.

There are two ways of doing this:
View->Code editor will show the built in code editor.
Alternatively you can use the DNC tool (View->DNC tool). Click on the options button and set the DNC function to ‘Run external command’. Turn on ‘Automatically send data’. In the Command box enter:
Notepad %f
This will open a copy of Notepad whenever you run the post processor. Note you have to keep the DNC tool open for this to work.