Not as elegant, but at least you don't need to create/delete the temp files yourself. Looking at the conversion commands suggests vim is using pipes, but it actually uses temporary files for the external filtering.Using this approach, there is no need for an external shell script which converts a plist file and then hands it off to vim. The file content is examined in vim and the result from the external conversion using plutil from the Apple Developer Tools is inserted in vim.All this should work even when working with several buffers (files), when reading a file into an existing buffer, or when only writing parts of a buffer to file.

If you open a binary file and just view it without making any changes, you can still exit from vim using the normal :q (no need for :q!) and the file is left untouched (still in binary format). If an originally-binary plist is saved as plain text due to syntax errors and you fix the errors and save the file again, it is written in binary format. If the file was not binary or if the conversion to binary fails (which can happen if you have syntax errors in your file), the file is stored in text format. When you save the file again, it is converted to binary again for writing if it was binary in the beginning.

What does it do? It reads a plist file, checks and memorizes if it is binary, converts it to plain text if necessary and turns on syntax highlinghting for XML. Note that this hint is obviously inspired by some other hints on the same topic but when using emacs. Using this vim script I created, you can use vim to automatically handle the plist files stored in binary format (new in 10.4). If you are like me and hate to use Apple's Property List Editor program with its limited capabilites to edit plist files (no searching, always starting with a view with all contents hidden etc.) and prefer to use vim instead for text editing, this one is for you.

Mac binary editor