• FORTH is the best for CLI and prototyping DML/DDL

Forth programming language

• extra compact primitive language without syntax in fact
• it has no syntax parser: you need only primitive lexer to implement the whole of language
• it is very easy and fast to rewrite your own FORTH implementation from scratch
• it uses concatenative programming paradigm via shared data stack
• unbeatable as a command shell interface with programming ability for tiny embedded systems starting from few Kb of RAM (cheapest microcontroller-based)
• can be good as DDL/DML/OML (object manipulation language) in a language-less programming systems

How to start

To feel the language you should take these books:

Starting FORTH

Very easy and fun intro to the language,

Starting FORTH (by) Leo Brodie

Thinking FORTH

If you want use it not only in command shell mode, but also write more complex programs, you can red this

Thinking Forth (c) Leo Brodie

Kelly, Spies FORTH (ru)

Келли,М. Спайс,Н. Язык программирования ФОРТ - М.: Радио и связь 1993 г. ISBN: 5-256-00438-7