Retrieve RAM info on a Mac?

Question

I need to retrieve the total amount of RAM present in a system and the total RAM currently being used, so I can calculate a percentage. This is similar to: Retrieve system infor

Answer 1

It's been 4 years but I just wanted to add some extra info on calculating total RAM.

To get the total RAM, we should also consider Pages occupied by compressor and Pages speculative in addition to Kyle Jones answer.

You can check out this post for where the problem occurs.