diff --git a/maintainers/scripts/rebuild-amount.sh b/maintainers/scripts/rebuild-amount.sh
new file mode 100755
index 000000000000..ebc5dc3b87ec
--- /dev/null
+++ b/maintainers/scripts/rebuild-amount.sh
@@ -0,0 +1,260 @@
+#!/bin/sh
+
+usage () {
+  echo 1>&2 "
+usage:
+  $0
+    [--git commit..commit | --git commit]
+    [--svn rev:rev | --svn rev]
+    [--path path[:path]*]
+    [--help]
+
+This program is used to investigate how any changes inside your nixpkgs
+repository may hurt.  With these kind of information you may choose wisely
+where you should commit your changes.
+
+This program adapts it-self to your versionning system to avoid too much
+effort on your Internet bandwidth.  If you need to check more than one
+commits / revisions, you may use the following commands:
+
+  --git remotes/trunk..master
+  --svn 17670:17677
+
+    Check the differences between each commit separating the first and the
+    last commit.
+
+  --path /etc/nixos/nixpkgs:/tmp/nixpkgs_1:/tmp/nixpkgs_2
+
+    Check the differences between multiple directories containing different
+    versions of nixpkgs.
+
+All these options exist with one commit / revision argument.  Such options
+are used to compare your \$NIXPKGS path with the specified version.
+
+If you omit to mention any other commit / revision, then your \$NIXPKGS path
+is compared with its last update.  This command is useful to test code from
+a dirty repository.
+
+"
+
+  exit 1;
+}
+
+#####################
+# Process Arguments #
+#####################
+
+: ${NIXPKGS=/etc/nixos/nixpkgs/}
+
+vcs=""
+gitCommits=""
+svnRevisions=""
+pathLocations=""
+verbose=false
+
+argfun=""
+for arg; do
+  if test -z "$argfun"; then
+    case $arg in
+      --git) vcs="git"; argfun="set_gitCommits";;
+      --svn) vcs="svn"; argfun="set_svnRevisions";;
+      --path) vcs="path"; argfun="set_pathLocations";;
+      --verbose) verbose=true;;
+      --help) usage;;
+      *) usage;;
+    esac
+  else
+    case $argfun in
+      set_*)
+        var=$(echo $argfun | sed 's,^set_,,')
+        eval $var=$arg
+        ;;
+    esac
+    argfun=""
+  fi
+done
+
+if $verbose; then
+  set -x
+else
+  set +x
+fi
+
+############################
+# Find the repository type #
+############################
+
+if test -z "$vcs"; then
+  if test -x "$NIXPKGS/.git"; then
+    if git --git-dir="$NIXPKGS/.git" branch > /dev/null 2>&1; then
+      vcs="git"
+      gitCommits=$(git --git-dir="$NIXPKGS/.git" log -n 1 --pretty=format:%H 2> /dev/null)
+    fi
+  elif test -x "$NIXPKGS/.svn"; then
+    cd "$NIXPKGS"
+    if svn info > /dev/null 2>&1; then
+      vcs="svn";
+      svnRevisions=$(svn info | sed -n 's,Revision: ,,p')
+    fi
+    cd -
+  else
+    usage
+  fi
+fi
+
+###############################
+# Define a storage directory. #
+###############################
+
+pkgListDir=""
+exitCode=1
+cleanup(){
+  test -e "$pkgListDir" && rm -rf "$pkgListDir"
+  exit $exitCode;
+}
+
+trap cleanup EXIT SIGINT SIGQUIT ERR
+
+pkgListDir=$(mktemp --tmpdir -d rebuild-amount-XXXXXXXX)
+vcsDir="$pkgListDir/.vcs"
+
+###########################
+# Versionning for Dummies #
+###########################
+
+path_init() {
+  if test "${pathLocations#*:}" = "$pathLocations"; then
+    pathLocations="$NIXPKGS:$pathLocations"
+  fi
+  pathLocations="${pathLocations}:"
+}
+
+path_getNext() {
+  pathLoc="${pathLocations%%:*}"
+  pathLocations="${pathLocations#*:}"
+}
+
+path_setPath() {
+  path="$pathLoc"
+}
+
+path_setName() {
+  name=$(echo "$pathLoc" | tr '/' '_')
+}
+
+################
+# Git Commands #
+################
+
+git_init() {
+  git clone "$NIXPKGS/.git" "$vcsDir" > /dev/null 2>&1
+  if echo "gitCommits" | grep -c "\.\." > /dev/null 2>&1; then
+    gitCommits=$(git --git-dir="$vcsDir/.git" log --reverse --pretty=format:%H $gitCommits 2> /dev/null)
+  else
+    pathLocations="$vcsDir:$NIXPKGS"
+    vcs="path"
+    path_init
+  fi
+}
+
+git_getNext() {
+  git --git-dir="$vcsDir/.git" checkout $(echo "$gitCommits" | head -n 1) > /dev/null 2>&1
+  gitCommits=$(echo "$gitCommits" | sed '1 d')
+}
+
+git_setPath() {
+  path="$vcsDir"
+}
+
+git_setName() {
+  name=$(git --git-dir="$vcsDir/.git" log -n 1 --pretty=format:%H  2> /dev/null)
+}
+
+#######################
+# Subversion Commands #
+#######################
+
+svn_init() {
+  cp -r "$NIXPKGS" "$vcsDir" > /dev/null 2>&1
+  if echo "svnRevisions" | grep -c ":" > /dev/null 2>&1; then
+    svnRevisions=$(seq ${svnRevisions%:*} ${svnRevisions#*:})
+  else
+    pathLocations="$vcsDir:$NIXPKGS"
+    vcs="path"
+    path_init
+  fi
+}
+
+svn_getNext() {
+  cd "$vcsDir"
+  svn checkout $(echo "$svnRevisions" | head -n 1) > /dev/null 2>&1
+  cd -
+  svnRevisions=$(echo "$svnRevisions" | sed '1 d')
+}
+
+svn_setPath() {
+  path="$vcsDir"
+}
+
+svn_setName() {
+  name=$(svn info  2> /dev/null | sed -n 's,Revision: ,,p')
+}
+
+####################
+# Logical Commands #
+####################
+
+init    () { ${vcs}_init; }
+getNext () { ${vcs}_getNext; }
+setPath () { ${vcs}_setPath; }
+setName () { ${vcs}_setName; }
+
+
+#####################
+# Check for Rebuild #
+#####################
+
+# Generate the list of all derivations that could be build from a nixpkgs
+# respository.  This list of derivation hashes is compared with previous
+# lists and a brief summary is produced on the output.
+
+compareNames () {
+    nb=$(diff -y --suppress-common-lines --speed-large-files "$pkgListDir/$1.drvs" "$pkgListDir/$2.drvs" 2> /dev/null | wc -l)
+    echo "$1 -> $2: $nb"
+}
+
+echo "Please wait, this may take some minutes ..."
+
+init
+first=""
+oldPrev=""
+
+prev=""
+curr=""
+
+while true; do
+  getNext
+  setPath # set path=...
+  setName # set name=...
+  curr="$name"
+
+  test -z "$curr" && break || true
+
+  nix-instantiate "$path" > "$pkgListDir/$curr.drvs" > /dev/null 2>&1 || true
+
+  if test -n "$prev"; then
+    compareNames "$prev" "$curr"
+  else
+    echo "Number of package to rebuild:"
+    first="$curr"
+  fi
+  oldPrev="$prev"
+  prev="$curr"
+done
+
+if test "$first" != "$oldPrev"; then
+  echo "Number of package to rebuild (first -> last):"
+  compareNames "$first" "$curr"
+fi
+
+exitCode=0