Shell script to create USB installer for OS X Yosemite

MakeYosemiteInstaller

#!/bin/sh

#  MakeYosemite.sh
#
#
#  Created by Johnykutty on 12/24/14.
#

red_color='\033[1;31m'
green_color='\033[0;32m'
endColor='\033[0m' # No Color

diskutil list

echo "Enter name of the disc you want to make bootable (choose from above): "
read usb_flash_drive

if disk_info=$(diskutil list $usb_flash_drive) ; then
echo "${green_color}Disk exists${endColor}"
else
echo "${red_color}$disk_info ${endColor}"
exit
fi

#Make sure user allows to erase the contents
echo "Do you want to erase all contents of $usb_flash_drive ? ${green_color}Y${endColor}/${red_color}N${endColor}"
read -p "" RESP

YES="y"
if echo $RESP | grep -i "^${YES}$" > /dev/null ; then
echo "${green_color}Erasing $usb_flash_drive .... "
else
echo "${red_color}Exiting...${endColor}"
exit
fi

echo "${green_color}Erasing $usb_flash_drive .... "

disk_name='Install_OS_X_Yosemite'
diskutil eraseDisk JHFS+  $disk_name $usb_flash_drive

echo "Enter full path to OS X Yosemite installer : ${end_color}"
read -r installer_path

if result=$(sudo "$installer_path"/Contents/Resources/createinstallmedia --volume /Volumes/$disk_name --applicationpath "$installer_path" --nointeraction) ; then
echo "${green_color}Completed process use  $disk_name to install OS X Yosemite and have fun :) ${endColor}"
else
echo "${red_color}Failed to create installer  $result ${endColor}"
fi

For and later use
sudo "$installer_path"/Contents/Resources/createinstallmedia --volume /Volumes/$disk_name
That is, we can skip --applicationpath "$installer_path"