XMLStarlet is a set of command line utilities (tools) which can be used to
transform, query, validate, and edit XML documents and files using simple set
of shell commands in similar way it is done for plain text files using UNIX
grep, sed, awk, diff, patch, join, etc commands.

This set of command line utilities can be used by those who deal with many XML
documents on UNIX shell command prompt as well as for automated XML processing
with shell scripts.