crosutils: refine image_to_usb progress output and performance

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.
@@ skipping 219 matching lines @@
       echo "device manually from outside the chroot and try again."
       echo
       exit 1
     fi
   done
   sleep 3
 
   if [ ${FLAGS_install} -ne ${FLAGS_TRUE} ]; then
     echo "Copying ${SRC_IMAGE} to ${FLAGS_to}..."
     if type pv >/dev/null 2>&1; then
-      sudo pv -ptre "${SRC_IMAGE}" | sudo dd of="${FLAGS_to}" bs=4M oflag=sync
+      # pv displays file size in k=1024 while dd uses k=1000.
+      # To prevent confusion, we suppress the summary report from dd.
+      sudo pv -ptreb -B 4m "${SRC_IMAGE}" |
+        sudo dd of="${FLAGS_to}" bs=4M oflag=sync status=noxfer
     else
       sudo dd if="${SRC_IMAGE}" of="${FLAGS_to}" bs=4M oflag=sync
     fi
     sync
   else
     if [ ${INSIDE_CHROOT} -ne 1 ]; then
       echo "Installation must be done from inside the chroot."
       exit 1
     fi
 
     echo "Installing ${SRC_IMAGE} to ${FLAGS_to}..."
     "${FLAGS_build_root}/${FLAGS_board}/usr/sbin/chromeos-install" \
       --yes \
       --skip_src_removable \
       --skip_dst_removable \
       --arch="${FLAGS_arch}" \
       --payload_image="${SRC_IMAGE}" \
       --dst="${FLAGS_to}"
   fi
   echo "Done."
 else
   # Output to a file, so just make a copy.
   echo "Copying ${SRC_IMAGE} to ${FLAGS_to}..."
   cp -f "${SRC_IMAGE}" "${FLAGS_to}"
 
   echo "Done.  To copy to a USB drive, do something like:"
   echo "   sudo dd if=${FLAGS_to} of=/dev/sdX bs=4M oflag=sync"
   echo "where /dev/sdX is the entire drive."
 fi