Be less verbose while changing the password. Add a script for checking if password already exists.

scripts/image_signing/set_chronos_password.sh

 #!/bin/bash
 
 # Copyright (c) 2010 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.
 
 # Customizes a Chrome OS release image by setting the chronos user password.
 
 # Usage: ./set_chronos_password.sh <image.bin> <chronos_password> [--force]
 
 # Load common constants and variables.
 . "$(dirname "$0")/common.sh"
 
 change_chronos_password() {
   local rootfs=$1
   local password=$2
-  echo "Changing chronos password to '$password'..."
+  echo "Setting chronos password..."
   local crypted_password="$(echo $password | openssl passwd -1 -stdin)"
   local temp_shadow="$rootfs/etc/tempshadow"
   echo "chronos:$crypted_password:14500:0:99999::::" \
     | sudo tee "$temp_shadow" > /dev/null
   sudo grep -Ev ^chronos: "$rootfs/etc/shadow" \
     | sudo tee -a "$temp_shadow" > /dev/null
   sudo mv -f "$temp_shadow" "$rootfs/etc/shadow"
 }
 
 main() {
@@ skipping 12 matching lines @@
     if ! no_chronos_password "$rootfs"; then
       echo "Password is already set [use --force if you'd like to update it]"
       exit 1
     fi
     # Prepare for remounting read/write.
     sudo umount -d $rootfs
   fi
   mount_image_partition "$image" 3 "$rootfs"
   change_chronos_password "$rootfs" "$chronos_password"
   touch "$image"  # Updates the image modification time.
-  echo "Password Changed."
+  echo "Password Set."
 }
 
 main $@