freeup is a tool to free up space on your disk. Generally utilities that do this show you a graphical picture of your files, with the idea that you explore the picture and find big files you can delete. To my mind this has two flaws: 1. It tends to reach a "steady state" where everything in the picture is something you've already looked at and decided you can't delete, so it takes some searching to find something you actually can get rid of. 2. It tends to show you big files (which are great when you can delete them), but not huge collections of little files (which are often a big consumer of disk space). freeup is designed to solve these problems in a straightforward way. Think of what it does as, every time you run it it throws a dart at the used space on your disk, and shows you the file where the dart landed. That solves problem #2. Then, it remembers where the dart landed, and for a reasonably long length of time it avoids that area when it's throwing darts. That solves problem #1. The simplest way to see it working is to try it. Every time you run it, it'll show you one file. See if you can delete that file (or other files in the immediate area, or other files like that file). Then repeat. It does caching of recently scanned filesystems, so it should be quick to run it multiple times, and it keeps a persistent record in ~/.freeup of what files it's examined in the at all recent past. That's it. Good luck!