image_to_usb: List available disks when /dev/sdX is specified

image_to_usb.sh

 #!/bin/bash
 
 # Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Script to convert the output of build_image.sh to a usb image.
 
 # Load common constants.  This should be the first executable line.
 # The path to common.sh should be relative to your script's location.
 . "$(dirname "$0")/common.sh"
 
 # Load functions and constants for chromeos-install
 . "$(dirname "$0")/chromeos-common.sh"
 
 get_default_board
 
 # Flags
 DEFINE_string board "${DEFAULT_BOARD}" "Board for which the image was built"
 DEFINE_string from "" \
   "Directory containing chromiumos_image.bin"
-DEFINE_string to "" "${DEFAULT_TO_HELP}"
+DEFINE_string to "/dev/sdX" "${DEFAULT_TO_HELP}"
 DEFINE_boolean yes ${FLAGS_FALSE} "Answer yes to all prompts" "y"
 DEFINE_boolean force_copy ${FLAGS_FALSE} "Always rebuild test image"
 DEFINE_boolean force_non_usb ${FLAGS_FALSE} \
   "Write out image even if target (--to) doesn't look like a USB disk"
 DEFINE_boolean factory_install ${FLAGS_FALSE} \
   "Whether to generate a factory install shim."
 DEFINE_boolean factory ${FLAGS_FALSE} \
   "Whether to generate a factory runin image. Implies aututest and test"
 DEFINE_boolean copy_kernel ${FLAGS_FALSE} \
   "Copy the kernel to the fourth partition."
@@ skipping 41 matching lines @@
 if [ -z "${FLAGS_from}" ]; then
   IMAGES_DIR="${DEFAULT_BUILD_ROOT}/images/${FLAGS_board}"
   FLAGS_from="${IMAGES_DIR}/$(ls -t ${IMAGES_DIR} 2>&-| head -1)"
 fi
 
 if [ ! -d "${FLAGS_from}" ] ; then
   echo "Cannot find image directory ${FLAGS_from}"
   exit 1
 fi
 
-if [ -z "${FLAGS_to}" ]; then
+if [ "${FLAGS_to}" == "/dev/sdX" ]; then
   echo "You must specify a file or device to write to using --to."
   disks=$(list_usb_disks)
   if [ -n "$disks" ]; then
     echo "Available USB disks:"
     for disk in $disks; do
       echo "  /dev/$disk:"
       echo "    Manufacturer: $(get_disk_info $disk manufacturer)"
       echo "         Product: $(get_disk_info $disk product)"
       echo "            Size: $[$(cat /sys/block/$disk/size) * 512] bytes"
     done
@@ skipping 132 matching lines @@
   echo "   sudo dd if=${FLAGS_to} of=/dev/sdX bs=4M"
   echo "where /dev/sdX is the entire drive."
   if [ ${INSIDE_CHROOT} -eq 1 ]
   then
     example=$(basename "${FLAGS_to}")
     echo "NOTE: Since you are currently inside the chroot, and you'll need to"
     echo "run dd outside the chroot, the path to the USB image will be"
     echo "different (ex: ~/chromeos/trunk/src/build/images/SOME_DIR/$example)."
   fi
 fi