diff --git a/plans/nest-simulator/3.1/default b/plans/nest-simulator/3.1/default
index 0d9edd3..64ad1c1 100644
--- a/plans/nest-simulator/3.1/default
+++ b/plans/nest-simulator/3.1/default
@@ -25,4 +25,5 @@ SHA256SUM=5c11dd6b451c4c6bf93037bf29d5231c6c75a0e1a8863344f6fb9bb225f279ca
 
 CMAKEFLAGS+=" -Dwith-boost=ON -Dwith-python=ON -Dwith-mpi=ON -Dwith-detailed-timers=ON -Dwith-ltdl=OFF"
 
+# shellcheck source=../common
 source "$(dirname "${PLAN}")/../common"
diff --git a/plans/nest-simulator/common b/plans/nest-simulator/common
index d7eb5d0..a1b1d25 100755
--- a/plans/nest-simulator/common
+++ b/plans/nest-simulator/common
@@ -62,7 +62,7 @@ module_install () {
 		log_status ">>> installing module file to ${module_path}"
 		mkdir -pv "$(dirname "${module_path}")"
 		module="$(cat "${PLAN}.module")"
-		if version_gt $BASH_VERSION 4.4; then
+		if version_gt "${BASH_VERSION}" "4.4"; then
 			echo -e "${module@P}" >"${module_path}"
 		else
 			# this is a bad substitute for the power of the bash>4.4 notation.
diff --git a/plans/nest-simulator/master/default b/plans/nest-simulator/master/default
index a91d7e6..d92f510 100644
--- a/plans/nest-simulator/master/default
+++ b/plans/nest-simulator/master/default
@@ -23,4 +23,5 @@ URL="https://github.com/nest/nest-simulator/archive/${VERSION}.tar.gz"
 
 CMAKEFLAGS+=" -Dwith-boost=ON -Dwith-python=ON -Dwith-mpi=ON -Dwith-detailed-timers=ON -Dwith-ltdl=OFF"
 
+# shellcheck source=../common
 source "$(dirname "${PLAN}")/../common"