WordPress.org Upgrade: FTP Credentials Required

Getting one of these screens while trying to upgrade or install a theme through the administrative interface on your WordPress.org blog?

WordPress.org Instance -  FTP Credentials Required

The fix is easy enough. If you’re running Apache2 as your webserver, you need to give whichever user Apache2 is running under (www-data by default on Debian) ownership of your WordPress directory:

chown -R www-data:www-data [your directory path here]

If leaving Apache with write makes you queasy, simply chown back after the upgrade:

chown -R [previous user]:[previous user] [your directory path here]