# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/http[s]?:\\/{2}.+\\/def/http:\/\/google.com\/def/g;t' <<< "<xml>http://localhost:8080/def/abc/xyx</xml>
<element xlink:href=\"http://localhostABCDEF/def/ABC/XYZ\">Some Text</element>"
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