The Free On-line Dictionary of Computing (30 December 2018):

Extended Tcl
TclX

    (TclX) Tcl extended by Mark Diekhans
    and Karl Lehenbauer from 1989 on with
   statements to provide high-level access Unix system
   primitives.

   TclX Home (http://neosoft.com/tclx/).

   E-mail: .

   (2003-02-12)