diff --git a/apollo.sh b/apollo.sh
index 490a955668392d879a74c60854972051506e56cb..2afe1e6c02dfaf95232d3709cd1389762d7dac71 100755
--- a/apollo.sh
+++ b/apollo.sh
@@ -63,20 +63,14 @@ function apollo_check_system_config() {
 function check_machine_arch() {
   # the machine type, currently support x86_64, aarch64
   MACHINE_ARCH=$(uname -m)
-
-  # Generate WORKSPACE file based on marchine architecture
-  if [ "$MACHINE_ARCH" == 'x86_64' ]; then
-    sed "s/MACHINE_ARCH/x86_64/g" WORKSPACE.in > WORKSPACE
-  elif [ "$MACHINE_ARCH" == 'aarch64' ]; then
-    sed "s/MACHINE_ARCH/aarch64/g" WORKSPACE.in > WORKSPACE
-  else
+  if [ "${MACHINE_ARCH}" != "x86_64" ] && [ "${MACHINE_ARCH}" != "aarch64" ]; then
     fail "Unknown machine architecture $MACHINE_ARCH"
     exit 1
   fi
 
   #setup vtk folder name for different systems.
   VTK_VERSION=$(find /usr/include/ -type d  -name "vtk-*" | tail -n1 | cut -d '-' -f 2)
-  sed -i "s/VTK_VERSION/${VTK_VERSION}/g" WORKSPACE
+  sed "s/VTK_VERSION/${VTK_VERSION}/g" WORKSPACE.in > WORKSPACE
 }
 
 function check_esd_files() {