Add a --no-prompt flag to install quietly.

build/install-build-deps.sh

 #!/bin/bash -e
 
 # Copyright (c) 2012 The Chromium 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 install everything needed to build chromium (well, ideally, anyway)
 # See http://code.google.com/p/chromium/wiki/LinuxBuildInstructions
 # and http://code.google.com/p/chromium/wiki/LinuxBuild64Bit
 
 usage() {
   echo "Usage: $0 [--options]"
   echo "Options:"
   echo "--[no-]syms: enable or disable installation of debugging symbols"
   echo "--[no-]lib32: enable or disable installation of 32 bit libraries"
+  echo "--no-prompt: silently select standard options/defaults"
   echo "Script will prompt interactively if options not given."
   exit 1
 }
 
 while test "$1" != ""
 do
   case "$1" in
   --syms)                   do_inst_syms=1;;
   --no-syms)                do_inst_syms=0;;
   --lib32)                  do_inst_lib32=1;;
   --no-lib32)               do_inst_lib32=0;;
+  --no-prompt)              do_default=1
+                            do_quietly="-qq --assume-yes"
+    ;;
   *) usage;;
   esac
   shift
 done
 
 if ! egrep -q \
     'Ubuntu (10\.04|10\.10|11\.04|11\.10|12\.04|lucid|maverick|natty|oneiric|precise)' \
     /etc/issue; then
   echo "Only Ubuntu 10.04 (lucid) through 12.04 (precise) are currently" \
       "supported" >&2
@@ skipping 78 matching lines @@
   lib_list="$lib_list appmenu-gtk"
 fi
 
 # Waits for the user to press 'Y' or 'N'. Either uppercase of lowercase is
 # accepted. Returns 0 for 'Y' and 1 for 'N'. If an optional parameter has
 # been provided to yes_no(), the function also accepts RETURN as a user input.
 # The parameter specifies the exit code that should be returned in that case.
 # The function will echo the user's selection followed by a newline character.
 # Users can abort the function by pressing CTRL-C. This will call "exit 1".
 yes_no() {
+  if [ 0 -ne "${do_default-0}" ] ; then
+    return $1
+  fi
   local c
   while :; do
     c="$(trap 'stty echo -iuclc icanon 2>/dev/null' EXIT INT TERM QUIT
          stty -echo iuclc -icanon 2>/dev/null
          dd count=1 bs=1 2>/dev/null | od -An -tx1)"
     case "$c" in
       " 0a") if [ -n "$1" ]; then
                [ $1 -eq 0 ] && echo "Y" || echo "N"
                return $1
              fi
@@ skipping 52 matching lines @@
 elif [ $? -eq 1 ]; then
   # We expect apt-get to have exit status of 1.
   # This indicates that we cancelled the install with "yes n|".
   new_list=$(echo "$new_list" |
     sed -e '1,/The following NEW packages will be installed:/d;s/^  //;t;d')
   new_list=$(echo "$new_list" | sed 's/ *$//')
   if [ -z "$new_list" ] ; then
     echo "No missing packages, and the packages are up-to-date."
   else
     echo "Installing missing packages: $new_list."
-    sudo apt-get install ${new_list}
+    sudo apt-get install ${do_quietly-} ${new_list}
   fi
   echo
 else
   # An apt-get exit status of 100 indicates that a real error has occurred.
 
   # I am intentionally leaving out the '"'s around new_list_cmd,
   # as this makes it easier to cut and paste the output
   echo "The following command failed: " ${new_list_cmd}
   echo
   echo "It produces the following output:"
@@ skipping 183 matching lines @@
              sed -e 's/[.]so[.][0-9].*/.so/' |
              sort -u); do
     [ "x${i##*/}" = "xld-linux.so" ] && continue
     [ -r "$i" ] && continue
     j="$(ls "$i."* | sed -e 's/.*[.]so[.]\([^.]*\)$/\1/;t;d' |
          sort -n | tail -n 1)"
     [ -r "$i.$j" ] || continue
     sudo ln -s "${i##*/}.$j" "$i"
   done
 fi