diff --git a/Tools/scripts/install-prereqs-ubuntu.sh b/Tools/scripts/install-prereqs-ubuntu.sh
index 1e4928b10c..ee3d3317ff 100755
--- a/Tools/scripts/install-prereqs-ubuntu.sh
+++ b/Tools/scripts/install-prereqs-ubuntu.sh
@@ -82,7 +82,7 @@ exportline="export PATH=$OPT/$ARM_ROOT/bin:\$PATH";
 grep -Fxq "$exportline" ~/.profile 2>/dev/null || {
     if maybe_prompt_user "Add $OPT/$ARM_ROOT/bin to your PATH [Y/n]?" ; then
         echo $exportline >> ~/.profile
-        $exportline
+        eval $exportline
     else
         echo "Skipping adding $OPT/$ARM_ROOT/bin to PATH."
     fi
@@ -92,7 +92,7 @@ exportline2="export PATH=$ARDUPILOT_ROOT/$ARDUPILOT_TOOLS:\$PATH";
 grep -Fxq "$exportline2" ~/.profile 2>/dev/null || {
     if maybe_prompt_user "Add $ARDUPILOT_ROOT/$ARDUPILOT_TOOLS to your PATH [Y/n]?" ; then
         echo $exportline2 >> ~/.profile
-        $exportline2
+        eval $exportline2
     else
         echo "Skipping adding $ARDUPILOT_ROOT/$ARDUPILOT_TOOLS to PATH."
     fi