Update install_tool script.

bin/install_tool

@@ -3,6 +3,7 @@
 set -ue
 
 REINSTALL=0
+PACKAGES=1
 
 while getopts -- "-:" a ; do
   case "${a}" in
@@ -11,6 +12,9 @@ while getopts -- "-:" a ; do
       reinstall)
         REINSTALL=1
         ;;
+      no-packages)
+        PACKAGES=0
+        ;;
       *)
         echo "Unknown long option ${OPTARG}" >/dev/stderr
         exit 1
@@ -20,7 +24,6 @@ while getopts -- "-:" a ; do
 done
 
 shift $(($OPTIND-1))
-echo $*
 
 if [ $# -ne 1 ] ; then
   echo "Usage: ${0} <tool>" >/dev/stderr
@@ -29,9 +32,13 @@ fi
 TOOL=${1}
 
 function install_pkgs {
+  if [ ${PACKAGES} -eq 0 ] ; then
+    return 0
+  fi
   if [ `id -u` -ne "0" ] ; then
     sudo apt-get -y install $* || (
-      echo "Unable to install packages, please ensure these are installed." >/dev/stderr
+      echo -n "Unable to install packages, please ensure these " >/dev/stderr
+      echo "are installed, then run with --no-packages." >/dev/stderr
       echo $*
       false )
     return 0