linux-usb

#!/bin/bash

IFS=$'\n'

# Helpers
function error {
  echo "${1}" >&2
  exit 1
}

function usage {
  echo "
    Create bootable Linux USB sticks from ISOs on macOS.

    Usage:
      ${program} [options] <iso>

    Options:
      -h, --help        Show this help.
  " | sed -E 's/^ {4}//'
}

# Checks
if [[ "${1}" =~ ^(-h|--help)$ ]]
then
  usage
  exit 0
fi

readonly linux_iso="${1}"

if [[ -z "${linux_iso}" || "$(file --mime-type --brief "${linux_iso}")" != 'application/x-iso9660-image'  ]]
then
  usage
  exit 1
fi

# Get disk to save to
readonly external_disks=($(diskutil list | grep '(external, physical)' | awk '{ print $1 }'))

[[ "${#external_disks[@]}" -lt 1 ]] && error 'Found no external disks. Connect one and run the script again.'

disks_with_info=()
disk_order='0'

for disk in "${external_disks[@]}"; do
  disk_order="$(bc <<< "${disk_order} + 1")"
  disk_size="$(diskutil info "${disk}" | grep 'Disk Size' | awk '{ print $3" "$4 }')"
  disks_with_info+=("[${disk_order}] ${disk} ${disk_size}")
done

while [[ -z "${disk_to_write_number}" ]] || [[ "${disk_to_write_number}" -lt 1 ]] || [[ "${disk_to_write_number}" -gt "${#disks_with_info[@]}" ]]; do
  echo 'Pick a disk do write to:'
  printf '%s\n' "${disks_with_info[@]}"
  echo
  read -r -p '> ' disk_to_write_number
done

readonly disk_to_write="$(sed "${disk_to_write_number}q;d" <<< "${disks_with_info[@]}" | awk '{ print $2 }')"

# Convert the Linux iso
readonly linux_dmg="$(mktemp).dmg"
hdiutil convert -quiet "${linux_iso}" -format UDRW -o "${linux_dmg}"

# Write to the disk
diskutil unmountDisk "${disk_to_write}"
echo 'Linux will now be saved to your USB flash drive. This should take a while. You may need to enter your password (for the write permissions).'
sudo dd if="${linux_dmg}" of="${disk_to_write}" status=progress

# eject disk
diskutil eject "${disk_to_write}"

echo 'Done. You now have a bootable Linux USB flash drive.'