diff --git a/epics-base.sh b/epics-base.sh
index 886ee5371..c4d4cd43b 100644
--- a/epics-base.sh
+++ b/epics-base.sh
@@ -1,6 +1,6 @@
 _OLD_EXTGLOB=$(shopt -p extglob)
 shopt -s extglob
 test -n "$EPICS_HOST_ARCH" || export EPICS_HOST_ARCH=$(/bin/sed "s%cpe:/o:redhat:enterprise_linux:\([0-9]*\).*%RHEL\1-`/bin/uname -m`%" /etc/system-release-cpe)
-PATH=${PATH//\/usr\/local\/epics\/base-+([0-9]).+([0-9]).+([0-9])\/bin\/$EPICS_HOST_ARCH}:$(echo $(ls -dvr /usr/local/epics/base-+([0-9]).+([0-9]).+([0-9])/bin/$EPICS_HOST_ARCH) | tr ' ' :)
+PATH=${PATH//?(:)\/usr\/local\/epics\/base-+([0-9]).+([0-9]).+([0-9])\/bin\/$EPICS_HOST_ARCH?(:)}:$(echo $(ls -dvr /usr/local/epics/base-+([0-9]).+([0-9]).+([0-9])/bin/$EPICS_HOST_ARCH) | tr ' ' :)
 eval $_OLD_EXTGLOB
 unset _OLD_EXTGLOB