Try removing the spaces before and after the semicolons (;) in your path variable.
Also, make sure you restart your terminal after you make any changes to the environment variables.
However, like I’ve mentioned in both my articles, you should migrate to using Rush. Just like you might have experienced it now, setting up the environment for using AI2 sources and/or extension template could be a bit tedious if you haven’t done something like that before.
Rush solves this issue to some extent. Instead of having to download and install ten different programs on your machine, you just need JDK 8 and Rush to start building extensions. On top of that, you get a bunch of cool new features, like faster builds, direct support for using Android manifest, etc., when using Rush.
To know more about what Rush is and how to install it, head over to the following post 