shell/LICENSE.md

GNU Lesser General Public License (LGPL)

I don't want it to be possible to make closed source forks of this. If you need to use this in a proprietary GO application, then compile this as a plugin. The BSD license is bad for core GO libraries.

(GO now supports plugins as of version 1.8) https://medium.com/@henvic/opensource-and-go-what-license-f6b36c201854