opml2urls
opml2urls converts a OPML XML to a list of urls for elements that have the xmlUrl attribute set.
Convert OPML XML to a list of plain text URLs from the xmlUrl attributes on the OPML.
cat subscriptions.xml | opml2urls > urls.txt
Convert an OPML XML file to the newsboart .newboat/urls
format.
cat subscriptions.xml | opml2urls -newsboat