In this quick little post I will show you how to resize your new Apple macOS High Sierra APFS volume. You may be asking well I can just resize it from my Disk Utility app. But alas, you can not. When you go into Disk Utility and select an APFS volume it says not resizable.
So how can you? Command line!
First, figure out your disk name and decide what size you want it to be.
Open up your terminal app and type:
After you find the disk you wanted (in this case disk1), you can run the next command to change the size. In my case, I have a 500GB drive and I wanted to reduce it to 400GB and use my remaining 100GB for another OS (Kali).
diskutil apfs resizeContainer disk1 400g
After this is finished you should have a shrunken drive.
Hope this helps someone that is trying to figure out how to resize a drive with the new APFS filesystem.