Add wiki-style license.

README.md

@@ -421,7 +421,6 @@ A few examples of piecing together commands:
 - `fortune`, `ddate`, and `sl`: um, well, it depends on whether you consider steam locomotives and Zippy quotations "useful"
 
 
-
 ## More resources
 
 - [awesome-shell](https://github.com/alebcay/awesome-shell): A curated list of shell tools and resources.
@@ -431,3 +430,10 @@ A few examples of piecing together commands:
 ## Disclaimer
 
 With the exception of very small tasks, code is written so others can read it. With power comes responsibility. The fact you *can* do something in Bash doesn't necessarily mean you should! ;)
+
+
+## License
+
+[![Creative Commons License](https://i.creativecommons.org/l/by-sa/4.0/88x31.png)](http://creativecommons.org/licenses/by-sa/4.0/) 
+
+This work is licensed under a [Creative Commons Attribution-ShareAlike 4.0 International Licene](http://creativecommons.org/licenses/by-sa/4.0/).