Tcl. As with other shells, the scripting model is based on commands and substitutions, but in Tcl substitution is more sane because a substitution is never rep

Tcl. As with other shells, the scripting model is based on commands and substitutions, but in Tcl substitution is more sane because a substitution is never reparsed and reinterpreted. Tcl was designed to provide a uniform scripting environment that could be extended into any problem domain. In this sense, is specifically intended as a generalization of the concept of a shell beyond interactive use by a logged-in user and into programmatic control of any set of subsystems. Tcl's syntax is more simple and more regular than other shells, and its semantics are designed to make it easy to create a DSL to manage the task at hand. Values are immutable in Tcl so it has the mathematical purity that is attractive in a functional language, but is much easier to get started with. Because every value is a string, there is a fexibility in Tcl that can not be found in other languages. Stringiness is interesting, fun, and productive.