Test XPath in the Terminal

There is a handy command-line tool to run XPath expressions and test them in the terminal on macOS.
The command is: xpath.

Assuming we have an XML file test.xml:

<books>
  <book id="123">
    <title>Book A</title>
  </book>
  <book id="456">
    <title>Book B</title>
  </book>
</books>

To test an XPath statement on this file, we can use:

$ xpath test.xml "//book[@id=456]"

Result:

Found 1 nodes:
-- NODE --
<book id="456">
  <title>Book B</title>
</book>

Note that the file argument is first and the XPath expression second, in double-quotes.