Creates a bootstick from archlinux based iso

bootstick.sh

#creates a bootstick from archlinux based iso

function usage() {
  echo "usage $0 /path/to/your_arch.iso /dev/sdX1"
  echo "example: $0 archlinux-2015.02.01-dual.iso /dev/sdb1"
  echo ""
  echo "/dev/sdX needs to have an ms-dos partition table"
  exit 1
}

function error() {
  echo "Error: $1"
  exit 1
}

#check for root
if [[ $EUID -ne 0 ]]; then
   error "This script must be run as root"
fi

#check for correct usage
if ! [[ $# -eq 2 ]] || [[ $1 != *linux-*.*.*.iso ]] || [[ $2 != /*/*1 ]]; then
  usage
fi

#check if required commands are present
commands="rsync mkdosfs mkdir sync grep lsblk extlinux fdisk dd umount mount"
for program in $commands; do
  if ! type $program &> /dev/null; then
    error "please install $program or the script cannot continue"
  fi
done

iso="$1"
if ! [ -f $iso ]; then
  error "$iso - file does not exist"
fi
label=$(echo "$iso" | grep -o -P '(?<=linux-).*(?=-)')
label="ARCH_${label:0:4}${label:5:2}"

usb="$2"
mnt=$(lsblk | grep -i ${usb:5:4})
if ! [[ $mnt ]]; then
  error "$usb - device not present"
fi

echo -n "Warning: all data on $usb will be lost, continue? [Y/n]: "
read cont
if [[ $cont ]] && [[ $cont != [Yy]* ]]; then
  echo "Exiting ..."
  exit 1
fi

mnt=$(echo "${mnt:6}" | grep -o -P '(?<=/).*')
if [[ $mnt ]]; then
  echo "Unmounting $usb at /$mnt ..."
  umount /$mnt
fi

echo "Formatting $usb to FAT32 with label $label ..."
mkdosfs -F 32 -n $label -I $usb
#uuid=$(blkid $usb -o value -s UUID)

echo "Copying data from $iso to $usb ..."
mkdir -p /mnt/{iso,usb}
mount -o loop $iso /mnt/iso
mount $usb /mnt/usb
rsync --progress -av /mnt/iso/* /mnt/usb
echo "Running sync (this may take a while) ..."
sync
umount /mnt/iso

echo "Copying syslinux files ..."
rsync --progress -rv /usr/lib/syslinux/bios/*.c32 /mnt/usb/arch/boot/syslinux
extlinux --install /mnt/usb/arch/boot/syslinux
umount /mnt/usb

boot=$(fdisk -l ${usb:0:-1} | grep -i "*" | grep -i "$usb")
if ! [[ $boot ]]; then
echo "Setting bootable flag on ${usb:0:-1} ..."
fdisk ${usb:0:-1}<<EOF
a
w
EOF
fi

echo "Installing MBR to ${usb:0:-1} ..."
dd bs=440 count=1 if=/usr/lib/syslinux/bios/mbr.bin of=${usb:0:-1}

echo "Finished!"