$ DYLD_INSERT_LIBRARIES=/path/to/your/Subclassedlibrary.dylib arch -i386 /Applications/OriginalApp.app/Contents/MacOS/OriginalApp &
And on a sidenote, I thought it was funny to see him refer to something as 'badly spelt' - I thought that 'rye' remark was a bit 'corny' (rimshot :-)
PS: I'm poking fun at myself—since I wrote the original app, including misspelling. Also, I use American english, but I do prefer to use the british form of 'spelt' or 'burnt.'
- I should not have written 'sub-classing'; this technique works by actually extending an existing class (Objective C allows you to extend a class)
- AFAIK this technique only works with Objective-C based apps.