::fixture-ready::
$ grep -o '<link>https://example.com/[^<]*</link>' public/feed.xml | sed 's#<link>##;s#</link>##'
https://example.com/blog/post.html
https://example.com/news/missing.html
::exit-code::0
$ grep -o '<link>https://example.com/[^<]*</link>' public/feed.xml | sed 's#<link>##;s#</link>##' | while read -r url; do grep -q "$url" public/sitemap.xml || echo "$url"; done
https://example.com/news/missing.html
::exit-code::0