diff --git a/vars/helper.groovy b/vars/helper.groovy
index ba7634a023421dbaf7755c28d1783882eb330bd0..499020f2b2281c22de37ae027c9633bc7e5c2370 100644
--- a/vars/helper.groovy
+++ b/vars/helper.groovy
@@ -170,10 +170,10 @@ def doTest(String label, String buildType) {
   // Copy test results files to the workspace, otherwise they are not available to the xunit plugin
   sh """
     cd /scratch/build-${JOB_NAME}
-    if [ -z "${CTESTOPTS}" ]; then
-      CTESTOPTS="${MAKEOPTS}"
+    if [ -z "\${CTESTOPTS}" ]; then
+      CTESTOPTS="\${MAKEOPTS}"
     fi
-    sudo -u msk_jenkins ctest --no-compress-output ${CTESTOPTS} -T Test -V || true
+    sudo -u msk_jenkins ctest --no-compress-output \${CTESTOPTS} -T Test -V || true
     sudo -u msk_jenkins sed -i Testing/*/Test.xml -e 's_\\(^[[:space:]]*<Name>\\)\\(.*\\)\\(</Name>\\)\$_\\1${label}.${buildType}.\\2\\3_'
     sudo -u msk_jenkins cp -r /scratch/build-${JOB_NAME}/Testing "${WORKSPACE}"
   """