Bootable usb flash drive for MacOS

bootable_usb4mac.sh

#!/bin/bash
# Usage: ./bootable_usb4mac.sh /dev/rdiskX isofile.iso
# Writing to /dev/rdiskX requires root privilegies, and rdisk is FASTER
# https://superuser.com/questions/631592/why-is-dev-rdisk-about-20-times-faster-than-dev-disk-in-mac-os-x/631601
USBDISK=$1
ISOFILE=$2
TMPFILE="tempoutput"

if [ "$(whoami)" != "root" ]; then
    echo "no root, qutting"
    exit 0
fi

echo "Write image $ISOFILE to $USBDISK, type YES to confirm:"

read INPUT
if [ "$INPUT" != "YES" ]; then
    echo "quitting"
    exit 0
fi

diskutil unmountDisk $USBDISK
hdiutil convert -format UDRW -o $TMPFILE $ISOFILE
dd if=$TMPFILE.dmg of=$USBDISK bs=1m
rm $TMPFILE.dmg