Add sudo_clobber and sudo_append functions so that we can "echo"

src/scripts/common.sh

 # 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.
 
 # Common constants for build scripts
 # This must evaluate properly for both /bin/bash and /bin/sh
 
 # All scripts should die on error unless commands are specifically excepted
 # by prefixing with '!' or surrounded by 'set +e' / 'set -e'.
 # TODO: Re-enable this once shflags is less prone to dying.
@@ skipping 131 matching lines @@
     echo
     echo
   fi
   ;;
 esac
 
 # -----------------------------------------------------------------------------
 # Functions
 
 function setup_board_warning {
-  echo  
-  echo "$V_REVERSE=================  WARNING  ======================$V_VIDOFF"  
+  echo
+  echo "$V_REVERSE=================  WARNING  ======================$V_VIDOFF"
   echo
   echo "*** No default board detected in " \
     "$GCLIENT_ROOT/src/scripts/.default_board"
   echo "*** Either run setup_board with default flag set"
   echo "*** or echo |board_name| > $GCLIENT_ROOT/src/scripts/.default_board"
   echo
 }
 
 
 # Sets the default board variable for calling script
 function get_default_board {
-  DEFAULT_BOARD= 
-  
+  DEFAULT_BOARD=
+
   if [ -f "$GCLIENT_ROOT/src/scripts/.default_board" ] ; then
     DEFAULT_BOARD=`cat "$GCLIENT_ROOT/src/scripts/.default_board"`
   fi
 }
 
 
 # Make a package
 function make_pkg_common {
   # Positional parameters from calling script.  :? means "fail if unset".
   set -e
@@ skipping 139 matching lines @@
 }
 
 # Removes single quotes around parameter
 # Arguments:
 #   $1 - string which optionally has surrounding quotes
 # Returns:
 #   None, but prints the string without quotes.
 function remove_quotes() {
   echo "$1" | sed -e "s/^'//; s/'$//"
 }
+
+# Writes stdin to the given file name as root using sudo in overwrite mode.
+#
+# $1 - The output file name.
+function sudo_clobber() {
+  sudo tee "$1" > /dev/null
+}
+
+# Writes stdin to the given file name as root using sudo in append mode.
+#
+# $1 - The output file name.
+function sudo_append() {
+  sudo tee -a "$1" > /dev/null
+}