Deet [L1 ] is a graphical debugger which can be easily retargetted to different languages, compilers, operating systems, etc. It does so by separating core debugger functionality from user interface. All debugger functionality is implemented with a small set of commands, called a nub. Nubs for Java and C exist (the distribution includes a C debugger written as a layer on top of gdb), and other instantiations are in development. Deet works with Tcl/Tk version 4.0 and up and with Tksh.