There’s an easier way. What you want is an app that opens OS X’s installer packages and lets you install only the components or individual files that you want. Yes, of course, there’s a Mac app for that.
The Selective Pacifist
Mac OS X has many components buried within the installer package. Most of us wouldn’t know how or where to look for the pieces, let alone know what to do if we found them.
Pacifist is the only Mac app I know of that opens up those .pkg installer packages so you can extract or install individual components.
What it does, at least, on the surface, is look inside package files, disk images, even .zip and .tar archives to pull out only those components you need to install or need to re-install.
Instead of installing the entire package and all the components inside, you get an option to select just what you need instead of everything, all or nothing.
Using Pacifist couldn’t be much easier, though knowing what to look for inside the package can be a plus.
What’s the benefit to using Pacifist?
First, it digs through old Mac OS X package files– the ones that install OS X (often found on DVDs, but downloadable these days from the Mac App Store).
It finds those individual apps and files you may need or want to reinstall on your Mac.
It’s all that and a little more, including an option to inspect a downloaded package (as when you use Software Update and download an app to update or install) to see what’s inside.
Pacifist also verifies existing app installations and can find missing or altered files, including kernel extensions (and checks to see what installer was used).
This is a notoriously geeky Mac app, that gives you an extra function to install a Mac app or component without having to install everything again.