xmllint - command line XML tool
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.
XMLStarlet - XMLStarlet Command Line XML Toolkit
Bracmat - Programming language for symbolic computation with extraordinary combination of pattern matching...
TXR - Pragmatic, convenient data munging language.
GNU sed - sed (stream editor) is a Unix utility that parses text and implements a programming language which...