diff --git a/src/minimal_overlay/bundles/coreutils/01_get.sh b/src/minimal_overlay/bundles/coreutils/01_get.sh
index 779eab667..06e0b57b3 100755
--- a/src/minimal_overlay/bundles/coreutils/01_get.sh
+++ b/src/minimal_overlay/bundles/coreutils/01_get.sh
@@ -4,35 +4,16 @@ set -e
 
 . ../../common.sh
 
-# Read the common configuration properties.
+# Read the 'coreutils' download URL from '.config'.
 DOWNLOAD_URL=`read_property COREUTILS_SOURCE_URL`
-USE_LOCAL_SOURCE=`read_property USE_LOCAL_SOURCE`
 
 # Grab everything after the last '/' character.
 ARCHIVE_FILE=${DOWNLOAD_URL##*/}
 
-if [ "$USE_LOCAL_SOURCE" = "true" -a ! -f $MAIN_SRC_DIR/source/overlay/$ARCHIVE_FILE ] ; then
-  echo "Source bundle $MAIN_SRC_DIR/source/overlay/$ARCHIVE_FILE is missing and will be downloaded."
-  USE_LOCAL_SOURCE="false"
-fi
+# Download 'coreutils' source archive in the 'source/overlay' directory.
+download_source $DOWNLOAD_URL $OVERLAY_SOURCE_DIR/$ARCHIVE_FILE
 
-cd $MAIN_SRC_DIR/source/overlay
-
-if [ ! "$USE_LOCAL_SOURCE" = "true" ] ; then
-  # Downloading coreutils source bundle file. The '-c' option allows the download to resume.
-  echo "Downloading coreutils source bundle from $DOWNLOAD_URL"
-  wget -c $DOWNLOAD_URL
-else
-  echo "Using local coreutils source bundle $MAIN_SRC_DIR/source/overlay/$ARCHIVE_FILE"
-fi
-
-# Delete folder with previously extracted coreutils.
-echo "Removing coreutils work area. This may take a while."
-rm -rf $WORK_DIR/overlay/$BUNDLE_NAME
-mkdir $WORK_DIR/overlay/$BUNDLE_NAME
-
-# Extract coreutils to folder 'work/overlay/coreutils'.
-# Full path will be something like 'work/overlay/coreutils/coreutils-8.28'.
-tar -xvf $ARCHIVE_FILE -C $WORK_DIR/overlay/$BUNDLE_NAME
+# Extract all 'coreutils' sources in the 'work/overlay/coreutils' directory.
+extract_source $OVERLAY_SOURCE_DIR/$ARCHIVE_FILE coreutils
 
 cd $SRC_DIR
diff --git a/src/minimal_overlay/bundles/coreutils/02_build.sh b/src/minimal_overlay/bundles/coreutils/02_build.sh
index 0bb145815..49d610be3 100755
--- a/src/minimal_overlay/bundles/coreutils/02_build.sh
+++ b/src/minimal_overlay/bundles/coreutils/02_build.sh
@@ -4,17 +4,12 @@ set -e
 
 . ../../common.sh
 
-cd $WORK_DIR/overlay/$BUNDLE_NAME
+cd $OVERLAY_WORK_DIR/$BUNDLE_NAME
 
 # Change to the coreutils source directory which ls finds, e.g. 'coreutils-8.28'.
 cd $(ls -d coreutils-*)
 
-if [ -f Makefile ] ; then
-  echo "Preparing '$BUNDLE_NAME' work area. This may take a while."
-  make -j $NUM_JOBS clean
-else
-  echo "The clean phase for '$BUNDLE_NAME' has been skipped."
-fi
+make_clean
 
 rm -rf $DEST_DIR
 
@@ -23,20 +18,15 @@ CFLAGS="$CFLAGS" ./configure \
   --prefix=/usr
 
 echo "Building '$BUNDLE_NAME'."
-make -j $NUM_JOBS
+make_target
 
 echo "Installing '$BUNDLE_NAME'."
-make -j $NUM_JOBS install DESTDIR=$DEST_DIR
+make_target install DESTDIR=$DEST_DIR
 
 echo "Reducing '$BUNDLE_NAME' size."
-set +e
-strip -g $DEST_DIR/usr/bin/*
-set -e
+reduce_size $DEST_DIR/usr/bin
 
-# With '--remove-destination' all possibly existing soft links in
-# '$OVERLAY_ROOTFS' will be overwritten correctly.
-cp -r --remove-destination $DEST_DIR/* \
-  $OVERLAY_ROOTFS
+install_to_overlay
 
 echo "Bundle '$BUNDLE_NAME' has been installed."
 
diff --git a/src/minimal_overlay/common.sh b/src/minimal_overlay/common.sh
index 4b58470f0..d11fa2e12 100755
--- a/src/minimal_overlay/common.sh
+++ b/src/minimal_overlay/common.sh
@@ -2,12 +2,15 @@
 
 set -e
 
-# common code used by all bundles
-# should be included at the top of every *.sh file of each bundle
+# Common code used by all bundles. Should be included at the
+# top of every *.sh file of each bundle.
 
-export MAIN_SRC_DIR=`realpath --no-symlinks $PWD/../../../`
-export WORK_DIR=$MAIN_SRC_DIR/work
 export SRC_DIR=`realpath --no-symlinks $PWD`
+export MAIN_SRC_DIR=`realpath --no-symlinks $SRC_DIR/../../../`
+export WORK_DIR=$MAIN_SRC_DIR/work
+export SOURCE_DIR=$MAIN_SRC_DIR/source
+export OVERLAY_WORK_DIR=$WORK_DIR/overlay
+export OVERLAY_SOURCE_DIR=$SOURCE_DIR/overlay
 export OVERLAY_ROOTFS=$WORK_DIR/overlay_rootfs
 export BUNDLE_NAME=`basename $SRC_DIR`
 export DEST_DIR=$WORK_DIR/overlay/$BUNDLE_NAME/${BUNDLE_NAME}_installed
@@ -33,33 +36,116 @@ read_property() (
 
   if [ ! "$prop_name" = "" ] ; then
     # Search in the main '.config' file.
-    prop_value=`grep -i ^${prop_name}= $CONFIG | cut -f2- -d'=' | xargs`
+    prop_value="`grep -i ^${prop_name}= $CONFIG | cut -f2- -d'=' | xargs`"
 
     if [ -f $SRC_DIR/.config ] ; then
       # Search in the local '.config' file.
-      prop_value_local=`grep -i ^${prop_name}= $SRC_DIR/.config | cut -f2- -d'=' | xargs`
+      prop_value_local="`grep -i ^${prop_name}= $SRC_DIR/.config | cut -f2- -d'=' | xargs`"
 
       if [ ! "$prop_value_local" = "" ] ; then
         # Override the original value with the local value.
-        prop_value=$prop_value_local
+        prop_value="$prop_value_local"
       fi
     fi
   fi
 
-  echo $prop_value
+  echo "$prop_value"
 )
 
-# Read the 'JOB_FACTOR' property from $CONFIG
-export JOB_FACTOR="$(grep -i ^JOB_FACTOR $CONFIG | cut -f2 -d'=')"
-
-# Read the 'CFLAGS' property from $CONFIG
-export CFLAGS="$(grep -i ^CFLAGS $CONFIG | cut -f2 -d'=')"
-
-# Find the number of available CPU cores
+# Read commonly used configuration properties.
+export JOB_FACTOR="`read_property JOB_FACTOR`"
+export CFLAGS="`read_property CFLAGS`"
 export NUM_CORES="$(grep ^processor /proc/cpuinfo | wc -l)"
 
 # Calculate the number of make "jobs"
-export NUM_JOBS=$((NUM_CORES * JOB_FACTOR))
+export NUM_JOBS="$((NUM_CORES * JOB_FACTOR))"
 
 # Ideally we would export MAKE at this point with -j etc to allow programs to just run $(MAKE) and not worry about extra flags that need to be passed
-#  export MAKE="${MAKE-make} -j $NUM_JOBS"
+# export MAKE="${MAKE-make} -j $NUM_JOBS"
+
+download_source() (
+  url=$1  # Download from this URL.
+  file=$2 # Save the resource in this file.
+
+  local=`read_property USE_LOCAL_SOURCE`
+
+  if [ "$local" = "true" -a ! -f $file  ] ; then
+    echo "Source file '$file' is missing and will be downloaded."
+    local=false
+  fi
+
+  if [ ! "$local" = "true" ] ; then
+    echo "Downloading overlay source file from '$url'."
+    echo "Saving overlay source file in '$file'".
+    wget -O $file -c $url
+  else
+    echo "Using local overlay source file '$file'."
+  fi
+)
+
+extract_source() (
+  file=$1
+  name=$2
+
+  # Delete folder with previously extracted source.
+  echo "Removing overlay work area for '$name'. This may take a while."
+  rm -rf $OVERLAY_WORK_DIR/$name
+  mkdir -p $OVERLAY_WORK_DIR/$name
+
+  # Extract source to folder 'work/overlay/$source'.
+  tar -xvf $file -C $OVERLAY_WORK_DIR/$name
+)
+
+make_target() (
+  make -j $NUM_JOBS "$@"
+)
+
+make_clean() (
+  target=$1
+
+  if [ "$target" = "" ] ; then
+    target=clean
+  fi
+
+  if [ -f Makefile ] ; then
+    echo "Preparing '$BUNDLE_NAME' work area. This may take a while."
+    make_target $target
+  else
+    echo "The clean phase for '$BUNDLE_NAME' has been skipped."
+  fi
+)
+
+reduce_size() (
+  while [ ! "$1" = "" ] ; do
+    if [ -d $1 ] ; then
+      for file in $1/* ; do
+        reduce_size $file
+      done
+    elif [ -f $1 ] ; then
+      set +e
+      strip -g $1
+      set -e
+    fi
+    
+    shift
+  done
+)
+
+install_to_overlay() (
+  # With '--remove-destination' all possibly existing soft links in
+  # '$OVERLAY_ROOTFS' will be overwritten correctly.
+
+  if [ "$#" = "2" ] ; then
+    cp -r --remove-destination \
+      $DEST_DIR/$1 \
+      $OVERLAY_ROOTFS/$2
+  elif [ "$#" = "1" ] ; then
+    cp -r --remove-destination \
+      $DEST_DIR/$1 \
+      $OVERLAY_ROOTFS
+  elif [ "$#" = "0" ] ; then
+    cp -r --remove-destination \
+      $DEST_DIR/* \
+      $OVERLAY_ROOTFS
+  fi
+)