diff --git a/free-programming-books.md b/free-programming-books.md
index e53a7f413bccbe32878f693b106dc7077b69edd4..25510c103ade7b9f03399d5ed746244985816d32 100644
--- a/free-programming-books.md
+++ b/free-programming-books.md
@@ -1766,6 +1766,7 @@ See also [LaTeX](#latex)
 * [Unix Toolbox](http://cb.vu/unixtoolbox.xhtml) - Colin Barschel
 * [UNIX Tutorial for Beginners](http://www.ee.surrey.ac.uk/Teaching/Unix/)
 * [Unix for Poets](http://www.stanford.edu/class/cs124/kwc-unix-for-poets.pdf) - Kenneth Ward Church (PDF)
+* [UNIX Commands and Concepts](http://www.cs.bu.edu/teaching/unix/reference/) - Robert I. Pitts
 
 
 ### Verilog