xmllint (on Linux) can be used the parse the XML file. The which command can be used to determine if xmllint is found in your $PATH.

which xmllint

If xmllint is in your $PATH, something like this should be returned.

/usr/bin/xmllint

If xmllint is not in your $PATH, xmllint is most likely not installed. In this scenario, apt-get or yum can be used to install xmllint.

yum install xmllint

Let's say you have an XML file named food.xml that contains the following.

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<root>
  <name>apple</name>
  <type>fruit</type>
</root>

The xmllint command followed by an XML file can be used to determine if the XML file has any syntax errors. Often, the --noout flag is included so that the content of the XML file is not outputted.

xmllint food.xml --noout

Then $? can be used to determine if the xmllint command returned 0 (success) or 1 (failed).

echo $?

Here is how you would return  the <name> tag.

xmllint --xpath //root//name food.xml

Or like this.

xmllint --xpath //name food.xml

Which should return the following.

<name>apple</name>

Here is how you would return the value in the <name> tag.

xmllint --xpath "string(//name)" food.xml

Which should return the following.

apple

If you have an XSD file, the --schema option can be used to validate the XML file against the XSD file.

xmllint --schema foo.xsd bar.xml --noout