# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/((<([a-zA-Z0-9]*:)*matchNode[^>]*)\\/\s*>)|(((<([a-zA-Z0-9]*:)*matchNode[\s\S]*?)>(([\s\S]*?)))<\\/([a-zA-Z0-9]*:)*matchNode>)/$2$6>(obfuscated...)<\/$3$7matchNode>/g;t' <<< "<?xml version=\"1.0\" encoding=\"UTF-8\"?>
<root xmlns:xx12=\"www.example.com\">
<xx12:matchNode so=\"what\">also matched</xx12:matchNode>
<matchNode/>
<matchNode>matched</matchNode>
<xx12:matchNode/>
<unmatchNode>
</unmatchNode>
<xx12:matchNode>also matched</xx12:matchNode>
<matchNode attr=\"12\" test=\"false\">
matched
</matchNode>
</root>"
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for SED, please visit: https://www.gnu.org/software/sed/manual/html_node/The-_0022s_0022-Command.html