The Tcl Tutor [L1 ] is a free, downloadable, multi-platform tutorial for Tcl. There are over 40 lessons, and each one shows sample code. What makes it even more useful is that the tutorial window has three panes; the first with the lesson, the second with editable sample code, and the third will let you run the sample code, completely self-contained. So you can change parts of the code and run the example, and see how your changes effected the output.