Obligatory warning: This script has been designated as an obsoleted "Retro Script". There is no guarantee that it will function as described with modern versions of iTunes and OS X. If used in its current form it may not work at all without modification and, at worst, it may corrupt or destroy data.
iTunes will stop updating a podcast if you have not listened to at least one of its episodes in five days. This script will batch-update every podcast subscription so you don't have to manually update each one individually.
I have posted instructions on how to create a launchd agent to run this script automatically and invisibly in the background to ensure that your Podcasts are always updated.
Possible iTunes bug (July 17, 2014): Looks like the iTunes AppleScript command updatePodcast command is broken as of iTunes 11.
downloaded 13m 7s ago
Change selected tracks' Start Time or Stop Time by user-entered seconds
downloaded 24m 53s ago
Move selected playlists to a new or existing folder
downloaded 30m 23s ago
Re-locate files of selected tracks to new folder, preserve track meta-data
downloaded 40m 17s ago
Copy files of tracks to selected folder
downloaded 44m 2s ago
Exports and then re-imports selected tracks' artwork
downloaded 1h 0m 59s ago
Remove iTunes tracks disassociated from files