How to Create a Ramdisk or Ramdrive in
In Ubuntu, there's already one created by default. It's located in
/dev/shm
and grows dynamically.
This will create a 550M ramdrive in /Volumes/ramdisk:
$ diskutil erasevolume HFS+ "ramdisk" `hdiutil attach -nomount ram://1165430`
To unmount, eject from Finder.