diff --git a/sit b/sit
index 1b406f6..d774ea5 100755
--- a/sit
+++ b/sit
@@ -32,6 +32,8 @@ function usage() {
     exit 0
 }
 
+# sit class file to be installed
+sit_classfile=$1
 # sit action to be performed
 sit_action=$2
 if [[ -n $sit_action ]] ; then
@@ -155,12 +157,11 @@ if [ ! -z "$MPI" ] ; then
     MPI_DIR=${MPI_DIR:=$(dirname $(dirname $(which $MPICC)))}
 fi
 
-SCLASSFILE=$1
 
-if [ -f $SCLASS_DIR/$SCLASSFILE ] ; then
-    source $SCLASS_DIR/$SCLASSFILE
+if [ -f $SCLASS_DIR/$sit_classfile ] ; then
+    source $SCLASS_DIR/$sit_classfile
 else
-    sit_fail "Could not find file $SCLASS_DIR/$SCLASSFILE"
+    sit_fail "Could not find file $SCLASS_DIR/$sit_classfile"
 fi
 
 PACKAGENAME=${PACKAGENAME:=$PACKAGE}
@@ -191,7 +192,7 @@ LOGDIR=${WORKDIR}
 # source the package class file a second time, so we can modify variables 
 # using their default values. (Defaults depend on other vairables in 
 # the class file like CATEGORY or PACKAGE)
-source $SCLASS_DIR/$SCLASSFILE
+source $SCLASS_DIR/$sit_classfile
 
 echo "Package name:        $PACKAGENAME"
 echo "Installation PREFIX: $PREFIX"