A command-line XML/XSLT toolkit. Note: You will likely need to know XPath: https://developer.mozilla.org/en-US/docs/Web/XPath. More information: https://xmlstar.sourceforge.net/docs.php.
stdout
:xmlstarlet format path/to/file.xml
stdin
:cat path/to/file.xml | xmlstarlet format
xmlstarlet select --template --copy-of xpath path/to/file.xml
stdout
(source file is unchanged):xmlstarlet edit --insert xpath --type attr --name attribute_name --value attribute_value path/to/file.xml
xmlstarlet edit --inplace --update xpath --value new_value file.xml
xmlstarlet edit --inplace --delete xpath file.xml
xmlstarlet [un]escape string
xmlstarlet ls path/to/directory