#! /bin/bash

set -e
set -u

size="${1:-128}"
name="${2:-bldisk}"

case "$(uname -s)" in
   Darwin )
      ((size*=2048)) #  2048 blocks per mb
      diskutil unmountDisk "$name" || true
      diskutil erasevolume HFS+ "$name" $(hdiutil attach -nomount ram://${size})
      ;;
   Linux )
      sudo umount /mnt/${name} || true
      sudo mkdir -p /mnt/${name}
      sudo mount -t tmpfs -o size=${size}M tmpfs /mnt/${name}
      ;;
   * )
      echo "Unknown uname $(uname -s)"
esac