GNU M4 - GNU M4 is an implementation of the m4 macro preprocessor.
GCC C Preprocessor (cpp) - Top (The C Preprocessor)
XMLStarlet - XMLStarlet Command Line XML Toolkit
PP - A generic Preprocessor - P is a text preprocessor designed for Pandoc (and more generally Markdown and reStructuredText).
GNU sed - sed (stream editor) is a Unix utility that parses text and implements a programming language which...
Bracmat - Programming language for symbolic computation with extraordinary combination of pattern matching...