Spice historically comes as a simulation engine with a Command Line Interface. The Spice engine can also be used with a Graphical User Interface. Tclspice represents a third approach to interfacing ngspice simulation functionality. Tclspice is nothing more than a new way of compiling and using SPICE source code. Spice is no longer considered as a standalone program but as a library invoked by a TCL interpreter. It either permits direct simulation in a TCL shell (this is quite analogous to the command line interface of ngspice), or it permits the elaboration of more complex, more specific, or more user friendly simulation programs, by writing TCL scripts.