diff --git a/packages/numlib/metis/5.1.0 b/packages/numlib/metis/5.1.0
index bff0f49..81ed7c2 100755
--- a/packages/numlib/metis/5.1.0
+++ b/packages/numlib/metis/5.1.0
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash -l
 # sit class file
 #
 # Christoph Niethammer <niethammer@hlrs.de> (C) 2012
diff --git a/sit b/sit
index 136b0fd..39533ce 100755
--- a/sit
+++ b/sit
@@ -1,4 +1,4 @@
-#!/bin/sh -l
+#!/bin/bash -l
 #
 # Install script inspired by the ebuild system of Gentoo Linux
 #
@@ -10,6 +10,14 @@ set -e
 # for debugging:
 # set -x 
 
+# Reading in execution option
+SIT_RUN_OPTION=$2
+if [[ -n $SIT_RUN_OPTION ]] ; then
+	echo "Executing with option: $SIT_RUN_OPTION"
+else
+	echo "Default execution"
+fi
+
 SIT_PATH=$(dirname $PWD/$0)
 SIT_CONFIG_FILE=$SIT_PATH/etc/sit.conf
 SIT_USER_CONFIG_FILE=$HOME/.sit
@@ -24,6 +32,8 @@ if [[ -e $SIT_CONFIG_FILE ]] ; then
 fi
 source "$SIT_PATH/functions.sh"
 
+sit_countdown 1
+
 # identify platform manually if no environment variable was set
 PLATFORM=${PLATFORM:=$SITE_PLATFORM_NAME}
 if [ -z $PLATFORM ]; then
@@ -179,13 +189,19 @@ echo "Logfile dir:         $LOGDIR"
 
 sit_countdown 3
 
-if [ -d ${WORKDIR} ] ; then
+# if working dir already exists and execution option is Default then remove
+# previous working directory and create new
+if [[ -d ${WORKDIR} && -z $SIT_RUN_OPTION ]] ; then
     sit_info "Removing existing working directory ${WORKDIR}"
     sit_countdown 5
     rm -rf ${WORKDIR}
 fi
-mkdir -p ${WORKDIR}
-mkdir -p ${BUILDDIR}
+
+if [ ! -d ${WORKDIR} ] ; then
+	mkdir -p ${WORKDIR}
+	mkdir -p ${BUILDDIR}
+fi
+
 if [ ! -z ${LOGDIR} ] ; then
     mkdir -p ${LOGDIR}
 else
@@ -193,6 +209,42 @@ else
     LOGDIR="/tmp"
 fi
 
+
+case $SIT_RUN_OPTION in
+"sitinfo")
+sit_sitinfo >> "$LOGDIR/sit_cmd.log"
+;;
+"unpack")
+sit_unpack    2>&1 | tee "$LOGDIR/unpack.log";       ( exit ${PIPESTATUS[0]} )
+;;
+"prepare")
+sit_prepare   2>&1 | tee "$LOGDIR/prepare.log";      ( exit ${PIPESTATUS[0]} )
+;;
+"configure")
+sit_configure 2>&1 | tee "$LOGDIR/configure.log";    ( exit ${PIPESTATUS[0]} )
+;;
+"build")
+sit_build     2>&1 | tee "$LOGDIR/make.log";         ( exit ${PIPESTATUS[0]} )
+;;
+"pretest")
+sit_pretest   2>&1 | tee "$LOGDIR/pretest.log";      ( exit ${PIPESTATUS[0]} )
+;;
+"install")
+sit_install   2>&1 | tee "$LOGDIR/make_install.log"; ( exit ${PIPESTATUS[0]} )
+;;
+"posttest")
+sit_posttest  2>&1 | tee "$LOGDIR/posttest.log";     ( exit ${PIPESTATUS[0]} )
+;;
+"postinst")
+sit_postinst  2>&1 | tee "$LOGDIR/postinst.log";     ( exit ${PIPESTATUS[0]} )
+;;
+"copy_logs")
+sit_copy_logs
+;;
+"setperms")
+sit_setperms
+;;
+"")
 sit_sitinfo >> "$LOGDIR/sit_cmd.log"
 sit_unpack    2>&1 | tee "$LOGDIR/unpack.log";       ( exit ${PIPESTATUS[0]} )
 sit_prepare   2>&1 | tee "$LOGDIR/prepare.log";      ( exit ${PIPESTATUS[0]} )
@@ -204,7 +256,25 @@ sit_install   2>&1 | tee "$LOGDIR/make_install.log"; ( exit ${PIPESTATUS[0]} )
 sit_posttest  2>&1 | tee "$LOGDIR/posttest.log";     ( exit ${PIPESTATUS[0]} )
 sit_postinst  2>&1 | tee "$LOGDIR/postinst.log";     ( exit ${PIPESTATUS[0]} )
 sit_copy_logs
-sit_setperms  
+sit_setperms
+;;
+*)
+echo "Argument $SIT_RUN_OPTION unrecognized."
+esac
+
+
+#sit_sitinfo >> "$LOGDIR/sit_cmd.log"
+#sit_unpack    2>&1 | tee "$LOGDIR/unpack.log";       ( exit ${PIPESTATUS[0]} )
+#sit_prepare   2>&1 | tee "$LOGDIR/prepare.log";      ( exit ${PIPESTATUS[0]} )
+#sit_configure 2>&1 | tee "$LOGDIR/configure.log";    ( exit ${PIPESTATUS[0]} )
+#sit_build     2>&1 | tee "$LOGDIR/make.log";         ( exit ${PIPESTATUS[0]} )
+
+#sit_pretest   2>&1 | tee "$LOGDIR/pretest.log";      ( exit ${PIPESTATUS[0]} )
+#sit_install   2>&1 | tee "$LOGDIR/make_install.log"; ( exit ${PIPESTATUS[0]} )
+#sit_posttest  2>&1 | tee "$LOGDIR/posttest.log";     ( exit ${PIPESTATUS[0]} )
+#sit_postinst  2>&1 | tee "$LOGDIR/postinst.log";     ( exit ${PIPESTATUS[0]} )
+#sit_copy_logs
+#sit_setperms  
 
 
 cat <<EOF