cookbook

What is the license for the code in the language cookbooks?

Question: 

What is the license for the code in the language cookbooks? Can the code be used in commercial projects?

Answer: 

The recipes in the language cookbooks are licensed under the BSD license, without the attribution clause (a.k.a. the "New BSD license").

This means that the code can be used in commercial and open source projects, including projects licensed under the GNU GPL (General Public License).