Comparing OPML Files, or How to Leave NetNewsWire

Recently I reached a level of excessive frustration with NetNewsWire (Mac) and decided it was time to move on. Problems with NetNewsWire include:

1. NetNewsWire has no way to sync its subscription list to match your Google Reader subscription list. There is a Merge button in the Preferences that sounds like it should do this, but it does not work correctly. Once your lists get out of sync, they generally stay that way.
2. NetNewsWire won’t prefetch images referenced in feeds. Without this, it is not useful for the most obvious purpose of a desktop reader: reading without a network connection. That’s a reasonable thing to leave out in early development, but in a mature product? What could they have been thinking?
3. NetNewsWire fails (silently) to subscribe to Google Alerts feeds, apparently because Google Reader already knows about those feeds… but see #1.
4. As many other users have reports, NetNewsWire frequently shows a different number of unread items from Google Reader, and no amount of Refreshing makes it match. The sync doesn’t quite work.

But to get rid of NetNewsWire, I needed to verify that I had all my feeds in Google Reader. This was easy:

1. Export OPML feed list from NNW
2. Export OPML feed list from Reader
3. Use a bit of perl regex and diff (below) to extract and compare just the list of feed URLs
4. Look over the diff, and copy-paste-subscribe the missing ones in Reader

The commands are:

perl -ne '/xmlUrl="([^"]*)"/ && print "$1\n"' <google-reader-subscriptions.xml  | sort >gr.urls
perl -ne '/xmlUrl="([^"]*)"/ && print "$1\n"' <nn.opml  | sort >nn.urls
diff gr.urls nn.urls

… which took much less time and far fewer keypresses than writing this post.

Offline reading is still very useful; at the moment I’m trying a combination of Google Reader, Gruml, and Reeder (iPad). Those work very well – so well that the risk of time-wasting feeds must be managed agressively: drop all but the most important, and don’t look every day.