Bootable ISO to USB disk for Mac OSX

iso2usb.sh

#!/bin/bash

##
# AUTHOR: Andy Savage <andy@savage.hk>
# GITHUB: www.github.com/hongkongkiwi
# DESCRIPTION: This script is for converting ISO files and burning them to a USB drive
##

HELP="USAGE: iso2usb blah.iso /dev/disk#"

ISOPATH="$1"
DEVPATH="$2"

# Check if a value exists in an array
# @param $1 mixed  Needle
# @param $2 array  Haystack
# @return  Success (0) if value exists, Failure (1) otherwise
# Usage: in_array "$needle" "${haystack[@]}"
# See: http://fvue.nl/wiki/Bash:_Check_if_array_element_exists
in_array() {
    local hay needle=$1
    shift
    for hay; do
        [[ $hay == $needle ]] && return 0
    done
    return 1
}

## If the user didn't pass a device to write to, we offer a selection
if [[ "$DEVPATH" == "" ]]; then
	DEVICES=`diskutil list | grep "/dev" | cut -d'(' -f1`
	OPTIONS=()
	OPTION_DEVICES=()
	while read -r DEVICE; do
    PROTOCOL=`diskutil info "$DEVICE" | grep 'Protocol:' | tr -d ' ' | cut -d':' -f2`
		if [[ "$PROTOCOL" == "USB" ]]; then
			DEVICE_SIZE=`diskutil info "$DEVICE" | grep 'Total Size:' | tr -d ' ' | cut -d':' -f2 | cut -d'(' -f1`
			DEVICE_NAME=`diskutil info "$DEVICE" | grep "Device / Media Name:" | cut -d':' -f2 | sed -e 's/^[[:space:]]*//'`

			OPTIONS+=("$DEVICE_NAME ($DEVICE_SIZE)")
			OPTION_DEVICES+=("$DEVICE")
		fi
	done <<< "$DEVICES"
	# Check if our devices list is empty
	if [ ${#OPTIONS[@]} -eq 0 ]; then
		echo "ERROR: Looks like there are no USB devices plugged in"
		exit 0
	fi
	OPTIONS+=("Quit")
	PS3='Please select USB device: '
	select CHOICE in "${OPTIONS[@]}"; do
		if [[ "$CHOICE" == "Quit" ]]; then
			exit 0
		elif [[ "$CHOICE" == "" ]]; then
			echo "Invalid Selection"
		elif [[ "$CHOICE" == "" ]]; then
			exit 0
		else
			in_array "$CHOICE" "$OPTIONS"
			DEVPATH=${OPTION_DEVICES[${?}]}
			break
		fi
	done
fi

if [[ ! -b "$DEVPATH" ]]; then
	echo "ERROR: Device not found. Aborting"
	echo
	echo "$HELP"
	exit 1
fi

# trap ctrl-c and call ctrl_c()
trap ctrl_c INT

# This just does some cleanup if necessary
function ctrl_c() {
	# Get rid of that pesky disk inserted is not readable error
	NOTIFICATION_PID=`ps axww | grep -i "[u]ser[n]otification[c]enter" | awk '{print $1}'`
	if [[ "$NOTIFICATION_PID" != "" ]]; then
		kill "$NOTIFICATION_PID"
	fi
	if [[ "$CONVERTED" == "YES" && -f "$DMGPATH" ]]; then
		rm "$DMGPATH"
	fi
	echo "ERROR: User Quit"
	exit 255
}

#### Some Useful Variables ####

#DEBUG="YES" # Set to Yes to avoid non-destructive actions
DEVINFO=`diskutil info "$DEVPATH" | grep 'Protocol' | tr -d ' ' | cut -d':' -f2`
DMGPATH=`mktemp -t 'iso2usb'`
ISOFILENAME=$(basename "$ISOPATH")
ISOEXT="${ISOFILENAME##*.}"
ISONAME="${ISOFILENAME%.*}"
DISKNUMBER=`basename "$DEVPATH"`
#add an 'r' to the beginning of the device name
#rdisk or raw disks write much faster
RDISKPATH="/dev/r$DISKNUMBER"
DISKSIZE=`diskutil info "$DEVPATH" | grep 'Total Size:' | tr -d ' ' | cut -d':' -f2 | cut -d'(' -f1`
DISKNAME=`diskutil info "$DEVPATH" | grep "Device / Media Name:" | cut -d':' -f2 | sed -e 's/^[[:space:]]*//'`

DDBSSIZE="1m"

PV_BIN=`which pv`

#### DO SOME SANITY CHECKING ###

PLATFORM='unknown'
UNAMESTR=`uname`
if [[ "$UNAMESTR" == 'Linux' ]]; then
	PLATFORM='linux'
elif [[ "$UNAMESTR" == 'FreeBSD' ]]; then
	PLATFORM='freebsd'
elif [[ "$UNAMESTR" == "Darwin" ]]; then
	PLATFORM="mac"
fi

if [[ "$PLATFORM" != "mac" ]]; then
		echo "ERROR: This script is designed only to run on Mac OSX"
		echo "       if you have some time, please help to improve it"
		echo "       and submit a pull request. I would appreciate it!"
fi

if [[ "$PV_BIN" == "" ]]; then
	echo "WARNING: pv is not installed. I recommend you install it to get better transfer progress info"
	echo "         if you have homebrew you can use 'brew install pv'"
fi

#check is script has been run as root /sudo
if [[ $UID != 0 ]]; then
	echo "Looks like your not running the script using sudo, we will do it for you"
	RESULT=`sudo -p "Please enter your user password so we can gain root privileges: " echo > /dev/null`
	if [[ $? != 0 ]]; then
		echo "ERROR: We were unable to get root privileges!"
		echo "       try running the script with sudo"
		exit 1
	fi
fi

if [[ ! -f "$ISOPATH" ]]; then
	echo "ERROR: ISO not found."
	echo "$HELP"
	exit 1
fi

if [[ `echo $ISOEXT | tr '[:upper:]' '[:lower:]'` != 'dmg' && `echo $ISOEXT | tr '[:upper:]' '[:lower:]'` != 'iso' ]]; then
	echo "ERROR: Accepted input ISO types are .iso or .dmg, anything else is not supported"
	exit 1
fi

#check if device is USB. Exit if device is not USB.
if [[ $DEVINFO != "USB" ]]; then
	echo "Non-USB device specified. This is dangerous and I assume a mistake."
	echo "Aborting."
	exit 1
fi

echo "Are you sure you want to write \"$ISONAME.$ISOEXT\" to \"$DISKNAME\" ($DISKSIZE)?"
read -p "WARNING: This is a destructive action! Proceed? (y/n)? " -n 1 -r
echo    # (optional) move to a new line
if [[ ! $REPLY =~ ^[Yy]$ ]]; then
	echo "ERROR: User Quit"
	exit 1
fi

if [[ "$DEBUG" == "YES" ]]; then
	echo "WARNING: Running in Debug mode! We won't actually do any destructive actions"
fi

if [[ `echo $ISOEXT | tr '[:upper:]' '[:lower:]'` == 'dmg' ]]; then
	echo "-> ISO file is actually a DMG file, skipping convert"
	DMGPATH="$ISOPATH"
else
	echo "-> Converting ISO to DMG file..."
	#convert the ISO to Mac format
	if [[ "$DEBUG" == "YES" ]]; then
		echo "hdiutil convert -format UDRW -o $DMGPATH $ISOPATH"
	fi
	if [[ -f "$DMGPATH" ]]; then
		rm "$DMGPATH"
	fi
	RESULT=`hdiutil convert -format UDRW -o "$DMGPATH" "$ISOPATH"`
	DMGPATH="$DMGPATH.dmg"

	#change the ownership of the new file to match the owner of the
	#current directory
	OWNER=$(ls -dl . | cut -d' ' -f4)
	GROUP=$(ls -dl . | cut -d' ' -f6)
	chown ${OWNER}:${GROUP} "$DMGPATH"
	CONVERTED="YES"
fi

# Unmount the device target device
if [[ $(mount | grep $DEVPATH) ]]; then
	RESULT=`diskutil unmountDisk $DEVPATH`
	echo "-> Unmounted disk $DEVPATH"
	sleep 2
	if [[ $(mount | grep $DEVPATH) ]]; then
		echo "ERROR: Unable to unmount target device."
		echo "Aborting."
		exit 1
	fi
fi

echo "-> Writing DMG file to device. This may take a while..."

#start the image writing process in the background
if [[ "$PV_BIN" == "" ]]; then
	if [[ "$DEBUG" == "YES" ]]; then
  	echo "sudo dd if=$DMGPATH of=$RDISKPATH bs=1m &"
  else
		sudo dd if="$DMGPATH" of="$RDISKPATH" bs=1m &
	fi

	# This is the awkward way of getting dd progress
	PID=$(ps | grep dd | grep -v grep)
	PID=$(echo $PID | cut -d' ' -f1)

	while [[ $(ps | grep $PID | grep -v grep) ]]
	do
		kill -INFO $PID
		sleep 10
	done
else
	# Progress using pv is much more interesting
	DMGSIZE=`ls -nl "$DMGPATH" | awk '{print $5}'`

	if [[ "$DEBUG" == "YES" ]]; then
		echo "dd if=$DMGPATH 2> /dev/null | pv --size $DMGSIZE -e -N 'Burning USB Drive' | sudo dd of=$RDISKPATH bs=1m >/dev/null 2>&1"
	else
		dd if="$DMGPATH" | pv --size $DMGSIZE -e -N 'Burning USB Drive' | sudo dd of="$RDISKPATH" bs="$DDBSSIZE" >/dev/null 2>&1
  fi
fi

# Get rid of that pesky disk inserted is not readable error
NOTIFICATION_PID=`ps axww | grep -i "[u]ser[n]otification[c]enter" | awk '{print $1}'`
if [[ "$NOTIFICATION_PID" != "" ]]; then
	sudo kill "$NOTIFICATION_PID"
fi

DISK_IS_MOUNTED=`diskutil list | grep "$DEVPATH"`
if [[ "$DISK_IS_MOUNTED" == "$DEVPATH" ]]; then
	# Eject the DISK
	RESULT=`diskutil eject "$DEVPATH"`
	echo "-> Finished. Disk is Ejected and is safe to remove."
fi

# Clear up converted DMG file if necessary
if [[ "$CONVERTED" == "YES" && -f "$DMGPATH" ]]; then
	if [[ "$DEBUG" != "YES" ]]; then
		rm "$DMGPATH"
	fi
	echo "-> Cleaned up temp dmg file"
fi

echo
echo "Note: If you want to use the disk now, please unplug and plug back in"
echo
echo "Have a nice day :-)"

exit 0