How can I build a Safari extension package from the command line?

Question

Instead of going to Extension Builder > Build Package…, I'd like to built a .safariextz package from the MyExtension.safariextension folder.

I know I can unpack an extension with xar -xf. I suspect the way back involves packing it with xar, but then I'll need to do the code signing thing, which may or may not involve codesign(1).

Answer 1

Looks like there is a way to patch XAR with a signature option. http://code.google.com/p/xar/issues/detail?id=76#c0