diff --git a/scripts/build-in-docker.sh b/scripts/build-in-docker.sh
index b6a1560..ac091ae 100755
--- a/scripts/build-in-docker.sh
+++ b/scripts/build-in-docker.sh
@@ -1,4 +1,5 @@
 #! /bin/bash -e
+set -o errtrace
 
 # build and test everything in a fresh docker installation
 img="ubuntu:latest"
@@ -39,21 +40,21 @@ while test $# -gt 0; do
             echo "    <os>:::<A>"
             echo "  Read as: On linux type <os> use <A> else use <B>"
             echo "  That means: If the distributer ID or codename in lsb_release"
-            echo "  matches <os>, then <A> is replaced, else <B> is replaced."
+            echo "  matches regular expression <os>, then <A> is replaced, else <B> is replaced."
             echo "  The three colons are for splitting <os> from <A> and <B> part."
             echo "  E.g.: Install package curl on wheezy and npm on olter systems:"
-            echo "    $0 -p wheezy:::curl:::npm"
+            echo "    $0 -p Debian|precise:::curl:::npm"
             echo
             echo "EXAMPLE:"
             echo
             echo "$0 -i mwaeckerlin/ubuntu:trusty-i386 \\"
-            echo "                    -t deb \\"
-            echo "                    -e ANDROID_HOME=/opt/local/android \\"
-            echo "                    -d /opt/local/android \\"
-            echo "                    -r universe \\"
-            echo "                    -r https://dev.marc.waeckerlin.org/repository \\"
-            echo "                    -k https://dev.marc.waeckerlin.org/repository/PublicKey \\"
-            echo "                    -p mrw-c++"
+            echo "                     -t deb \\"
+            echo "                     -e ANDROID_HOME=/opt/local/android \\"
+            echo "                     -d /opt/local/android \\"
+            echo "                     -r universe \\"
+            echo "                     -r https://dev.marc.waeckerlin.org/repository \\"
+            echo "                     -k https://dev.marc.waeckerlin.org/repository/PublicKey \\"
+            echo "                     -p mrw-c++"
             echo
             exit 0
             ;;
@@ -93,6 +94,38 @@ while test $# -gt 0; do
     shift
 done
 
+function traperror() {
+    set +x
+    local DOCKER_ID="$1"
+    local err=($2) # error status
+    local line="$3" # LINENO
+    local linecallfunc="$4" 
+    local command="$5"
+    local funcstack="$6"
+    for e in ${err[@]}; do
+        if test -n "$e" -a "$e" != "0"; then
+            echo "<---"
+            echo "ERROR: line $line - command '$command' exited with status: $e (${err[@]})"
+            if [ "${funcstack}" != "main" -o "$linecallfunc" != "0" ]; then
+                echo -n "   ... Error at ${funcstack} "
+                if [ "$linecallfunc" != "" ]; then
+                    echo -n "called at line $linecallfunc"
+                fi
+                echo
+            fi
+            echo "**** Entering docker container ${DOCKER_ID}, exit with Ctrl-D"
+            echo -n "   ... cleanup docker: "
+            docker rm -f "${DOCKER_ID}"
+            echo "returning status: $e"
+            echo "--->"
+            exit $e
+        fi
+    done
+    echo -n "   SUCCESS ... cleanup docker: "
+    docker rm -f "${DOCKER_ID}"
+    exit 0
+}
+
 function ifthenelse() {
     arg="$1"
     shift
@@ -103,24 +136,29 @@ function ifthenelse() {
         os="${arg%%:::*}"
         thenpart="${arg#*:::}"
         if test "${thenpart/:::/}" = "${thenpart}"; then
-            docker exec ${DOCKER_ID} bash -c 'os="'$os'"; if test "${os//$(lsb_release -is)/}${os//$(lsb_release -cs)/}" != "${os}${os}"; then '"${cmd//ARG/${thenpart}}"'; fi'
+            docker exec ${DOCKER_ID} bash -c 'os="'$os'"; if [[ "$(lsb_release -is)-$(lsb_release -cs)" =~ ${os} ]]; then '"${cmd//ARG/${thenpart}}"'; fi'
         else
             elsepart="${thenpart##*:::}"
             thenpart="${thenpart%:::*}"
-            docker exec ${DOCKER_ID} bash -c 'os="'$os'"; if test "${os//$(lsb_release -is)/}${os//$(lsb_release -cs)/}" != "${os}${os}"; then '"${cmd//ARG/${thenpart}}"'; else '"${cmd//ARG/${elsepart}}"'; fi'
+            if test -n "${thenpart}"; then
+                docker exec ${DOCKER_ID} bash -c 'os="'$os'"; if [[ "$(lsb_release -is)-$(lsb_release -cs)" =~ ${os} ]]; then '"${cmd//ARG/${thenpart}}"'; else '"${cmd//ARG/${elsepart}}"'; fi'
+            else
+                docker exec ${DOCKER_ID} bash -c 'os="'$os'"; if [[ "$(lsb_release -is)-$(lsb_release -cs)" =~ ${os} ]]; then true; else '"${cmd//ARG/${elsepart}}"'; fi'
+            fi    
         fi
     fi
 }
 
 set -x
 
+docker pull $img
 DOCKER_ID=$(docker run -d ${dirs[@]} ${envs[@]} -w /workdir $img sleep infinity)
-trap "docker rm -f ${DOCKER_ID}" INT TERM EXIT
+trap 'traperror '"${DOCKER_ID}"' "$? ${PIPESTATUS[@]}" $LINENO $BASH_LINENO "$BASH_COMMAND" "${FUNCNAME[@]}" "${FUNCTION}"' SIGINT INT TERM EXIT
 docker exec ${DOCKER_ID} apt-get update
-docker exec ${DOCKER_ID} apt-get upgrade -y --force-yes
-if ! docker exec ${DOCKER_ID} apt-get install -y --force-yes python-software-properties apt-transport-https dpkg-dev lsb-release; then
-    docker exec ${DOCKER_ID} apt-get install -y --force-yes software-properties-common apt-transport-https dpkg-dev lsb-release
-fi
+docker exec ${DOCKER_ID} apt-get upgrade -y
+docker exec ${DOCKER_ID} apt-get install -y python-software-properties software-properties-common apt-transport-https dpkg-dev lsb-release || \
+    docker exec ${DOCKER_ID} apt-get install -y software-properties-common apt-transport-https dpkg-dev lsb-release || \
+    docker exec ${DOCKER_ID} apt-get install -y python-software-properties apt-transport-https dpkg-dev lsb-release;
 for repo in "${repos[@]}"; do
     ifthenelse "${repo}" "apt-add-repository ARG"
 done