Internal Program Version: TCL  8.6.15

Tcl (Tool Command Language) is a very powerful but easy to learn
dynamic programming language, suitable for a very wide range of uses,
including web and desktop applications, networking, administration,
testing and many more. Open source and business-friendly, Tcl is a
mature yet evolving language that is truly cross platform, easily
deployed and highly extensible.

http://www.tcl.tk