Seconded. My first (and only to date) serious encounter with Tcl was when writing some `expect' scripts. The language is flexible and powerful. It's quite easy

Seconded. My first (and only to date) serious encounter with Tcl was when writing some `expect' scripts. The language is flexible and powerful. It's quite easy to pick up the basics and become productive. Tcl is pretty good with GUI -- for example, Git's gui (`gitk' and `git gui') are implemented in Tcl with Tk library. By default it looks very plain, but is of course skinnable. NB., `expect' is a great way of automating CLI interaction with remote devices during development and testing. In a way `expect' reminds me of Awk -- `expect' is data driven as well, actions are attached to specificators of input conditions.