ramdisk create/delete/list on macOS

ramdisk.sh

#!/bin/bash

# From http://tech.serbinn.net/2010/shell-script-to-create-ramdisk-on-mac-os-x/

E_BADARGS=99

baseName=$(basename $0)

function printHelp() {
  >&2 echo -e "\nUsage: "
  >&2 echo "${baseName} create SIZE_IN_MB [VOLUME_NAME]"
  >&2 echo -e "\tcreate a new ramdisk"
  >&2 echo -e "\tVOLUME_NAME defaults to 'ramdisk' if not provided"
  >&2 echo -e "\te.g create a 100MB volume under /Volumes/Flerb: ${baseName} create 100 Flerb"
  >&2 echo " "
  >&2 echo "${baseName} destroy DEVICE_PATH"
  >&2 echo -e "\tunmount and detach device at DEVICE_PATH (DOES NOT CHECK IF IT'S ACTUALLY A RAMDISK)"
  >&2 echo -e "\tDEVICE_PATH can be found with 'mount'. Usually /dev/diskN where N is a number"
  >&2 echo -e "\te.g. ${baseName} destroy /dev/disk3"
  >&2 echo " "
  >&2 echo "${baseName} list"
  >&2 echo -e "\tlist ramdisk device paths. Format is"
  >&2 echo -e "\t/dev/disk3 (mounted at /Volumes/Flerb)"
  >&2 echo " "
}

function charg() {
if [[ -z "$1" ]]
then
  >&2 echo expected argument missing
  printHelp
  exit $E_BADARGS
fi
}

function createDisk() {
  charg "$1"
  >&2 echo "Creating ramdisk"
  RAMDISK_SIZE_MB=$1
  RAMDISK_SECTORS=$((2048 * $RAMDISK_SIZE_MB))
  DEVICE_PATH=$(hdiutil attach -nomount ram://$RAMDISK_SECTORS)
  >&2 echo "Disk ID is:"
  echo ${DEVICE_PATH}
  diskutil erasevolume HFS+ "${3:-ramdisk}" ${DEVICE_PATH}
}

function listRamdisks() {
  hdiutil info -plist | /usr/bin/xmllint --xpath "//key[.='images']/following-sibling::array/dict/key[.='image-path']/\
following-sibling::string[contains(., 'ram')]/parent::*/key[.='system-entities']/following-sibling::array/dict/key[.='dev-entry' \
or .='mount-point']/following-sibling::string[1]/text()" - | sed -E $'s!/dev/!\\\n&!g'|sed -E 's!/(Volumes/.+)! (mounted at &)!g'|tail -n+2
}

function destroyDisk() {
  charg "$1"
  >&2 echo "unmounting and detaching $1"
  umount -f $1
  hdiutil detach $1
}

case "$1" in
  create) createDisk $2 $3 ;;
  destroy) destroyDisk $2 ;;
  list) listRamdisks ;;
  *) >&2 echo "'${1}' ain't no command I've ever heard of";printHelp;exit $E_BADARGS ;;
esac

Revision 3 has an error: Not possible to change the name of the mount in /Volumes/

Very easy fix: Just change $3 to $2 in https://gist.github.com/ORBAT/df150a3c8464557481c4147d3916ab19#file-ramdisk-sh-L44

-  diskutil erasevolume HFS+ "${3:-ramdisk}" ${DEVICE_PATH}
+  diskutil erasevolume HFS+ "${2:-ramdisk}" ${DEVICE_PATH}