None of the documentation indicates where the environment configuration file is
the only hint is the line printed when you run ./ipdk install, it tells you that it is at ~/.ipdk/ipdk.env'
The various .md files talk about the configuration file in many places, and even have links to pages supposedly to give you more info, but not a single one that I found (I searched through all of them) tells you where the file actually is.
So if you do not see that single line, when you run ./ipdk install, you are forced to go rummaging through scripts to figure out where to find the file. I spent a good hour doing so.
@PatrickKutch - Thanks for reporting. Will take care of necessary updates in the documentation to provide more details on the configuration file path.