XMLStarlet Toolkit: query, edit, check, convert and transform XML documents. Some subcommands such as
xml validatehave their own usage documentation. More information: https://xmlstar.sourceforge.net/docs.php.
xml --help
stdout:xml subcommand options path/to/input.xml|URI
stdin and stdout:xml subcommand options
xml subcommand options path/to/input.xml|URI > path/to/output
xml subcommand --help
xml --version