[Bug-gnupod] In lieu of modify, here's gnupod_alter.pl

[Philip Hazelden]

I've written a script, gnupod_alter.pl, to make changes to the gnutunesdb.xml file. If anyone wants to use it, it's available at http://github.com/ChickenProp/gnupod-patches under the 'alter' branch.

I freely admit that the interface is pretty horrible. On the command line you specify an attribute to filter based on, and more attributes to edit. Then on stdin you pass the values for each of these attributes. It's optimised for taking output from dumpsongs[1], passed through unix filters. Which I guess is useful if you want to rot13 all your track names or something, but not so much for anything that I've actually wanted to do. At some point I'll probably start to allow something like `gnupod_alter.pl id=123 album=foo artist=bar`. (Which currently would be written `echo 123\tfoo\tbar | gnupod_alter.pl id album artist`, and would set the album and artist of track 123.) Or feel free to do it yourself and send a pull request.

The other thing you can do is update the music file on the ipod with one on disk, by using the nonattribute 'file'. I intend to add a nonattribute 'file-from-dir' which attempts to find the right track in a directory. Other things which I might add include a way to copy metadata from a file on disk (and possibly also update the file itself), and a way to add/remove tracks from playlists.

Obviously, use at your own risk. I've tried to avoid data loss as much as possible, by not making any changes until the very end and bailing if anything goes wrong before then. (Except that I don't yet check whether the file you're trying to update from exists. I assume that if it doesn't, nothing gets deleted, but that's down to File::Copy. I recommend not trying to update from files that don't exist.) If you want to see what's going to happen (or if you have a backup gnutunesdb.xml but no mounted ipod), you can tell it to work on a file other than the default with the -f option. In that case it won't update any files, even if the ipod is mounted, but it will say that it's updating them.

[1] gnupod_dumpsongs.pl is another script I wrote, also available in the above github project under the branch 'dumpsongs'. It does basically the same thing as gnupod_find.pl.