I've got no experience in Applescript, so my advice might not be worth much. That said, since you have three problems, solve them each on their own: * First, d

I've got no experience in Applescript, so my advice might not be worth much. That said, since you have three problems, solve them each on their own: * First, do something really simple with Regex, to make sure you can use them in your app (say, in JS, it'd be something like alert('test'.replace(/st/, 'ssst')); Then you know the regex engine itself is working. * Next, you need to figure out how to change text in the document. Not sure if you have already got this covered. * Then it's a matter of applying the two. Note that regex functions return the changed string, rather than change the string itself. In the example listed on the documentation it does: set s to change "^[ ]+" into "" in s with regexp i.e. first change the string (change "^[ ]+" into "" in s with regexp) then store it (set s to <expr> All in all pretty vague advice I guess.