tkDerm is written by a programming language called Tcl/Tk.
Tcl stands for Tool Command Language. It was designed and developed in 1980's by Professor John Ousterhout of the University of California, Berkley.
Tk is a graphical user-interface toolkit associated with Tcl, which is developed for programmers to craft buttons, windows or other widgets with minimum effort.
As a whole, Tcl and Tk are often referred as Tcl/Tk.
For Windows and Macintosh, tkDerm is also provided as the starpack version, which doesn't require the Tcl/Tk runtime environment, in addition to the usual script version. Linux users can get only the script version of tkDerm.
Caution : The starpack version of tkDerm, whose name contains the platform name such as win or mac, doesn't require installation of Tcl/Tk, whereas the script version can't work without the Tcl/Tk runtime.