diff --git a/toil_examples/source_selection.sh b/toil_examples/source_selection.sh
index 39502c5b..530681e7 100644
--- a/toil_examples/source_selection.sh
+++ b/toil_examples/source_selection.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-#NOTE: WORKS ONLY FROM TOIL>6.0.0
+#NOTE: works only with TOIL>6.0.0
 
 #### UPDATE THESE ####
 
@@ -27,13 +27,13 @@ if [[ "$CONTAINERSTR" == *"apptainer"* ]]; then
   export APPTAINER_TMPDIR=$APPTAINER_CACHEDIR/tmp
   export APPTAINER_PULLDIR=$APPTAINER_CACHEDIR/pull
   export APPTAINER_BIND=$SING_BIND
-  export APPTAINERENV_PYTHONPATH='$VLBI_SCRIPTS:$PYTHONPATH'
+  export APPTAINERENV_PYTHONPATH='${VLBI_SCRIPTS}:$PYTHONPATH'
 else
   export SINGULARITY_CACHEDIR=$PWD/singularity
   export SINGULARITY_TMPDIR=$SINGULARITY_CACHEDIR/tmp
   export SINGULARITY_PULLDIR=$SINGULARITY_CACHEDIR/pull
   export SINGULARITY_BIND=$SING_BIND
-  export SINGULARITYENV_PYTHONPATH='$VLBI_SCRIPTS:$PYTHONPATH'
+  export SINGULARITYENV_PYTHONPATH='${VLBI_SCRIPTS}:$PYTHONPATH'
 fi
 
 export CWL_SINGULARITY_CACHE=$APPTAINER_CACHEDIR