GNU M4 - GNU M4 is an implementation of the m4 macro preprocessor.
xmllint - command line XML tool
XMLStarlet - XMLStarlet Command Line XML Toolkit
Xidel - Xidel is a command line tool to download html/xml pages and extract data from them using CSS 3 selectors, XPath 3 expressions or pattern-matching templates.
GPP - GPP is a general-purpose preprocessor with customizable syntax, suitable for a wide range of...
Bracmat - Programming language for symbolic computation with extraordinary combination of pattern matching...