Bash function for creating a ram disk in OS X 10.7+

ramdisk.sh

#!/bin/sh

# usage: mkramdisk 1024 ~/scratch

function mkramdisk() {
  ramfs_size_mb=$1
  mount_point=$2
  ramfs_size_sectors=$((${ramfs_size_mb}*1024*1024/512))
  ramdisk_dev=`hdid -nomount ram://${ramfs_size_sectors}`
  newfs_hfs -v 'ram disk' ${ramdisk_dev}
  mkdir -p ${mount_point}
  mount -o noatime -t hfs ${ramdisk_dev} ${mount_point}
    
  echo "remove with:"
  echo "umount ${mount_point}"
  echo "diskutil eject ${ramdisk_dev}"
}