Create APFS RAM disk on macOS High Sierra

Question

usually creating RAM disks works with the following commands

hdid -nomount ram://

Returns e.g. /dev/disk2 Then I would format

Answer 1

@Glyph provided the best answer in a comment to the accepted answer, but it deserves its own answer:

diskutil partitionDisk $(hdiutil attach -nomount ram://$((2048*sizeInMB))) 1 GPTFormat APFS 'Ramdisk' '100%'

Change sizeInMB to your desired size.

I've updated Glyph's answer to simplify the volume name a little.