GNU M4 - GNU M4 is an implementation of the m4 macro preprocessor.
Gema - General purpose text macro processor.
XMLStarlet - XMLStarlet Command Line XML Toolkit
GCC C Preprocessor (cpp) - Top (The C Preprocessor)
xmllint - command line XML tool
GNU sed - sed (stream editor) is a Unix utility that parses text and implements a programming language which...