diff --git a/.env.airflow.sample b/.env.airflow.sample
index 7031c3d9..302be2f1 100644
--- a/.env.airflow.sample
+++ b/.env.airflow.sample
@@ -1,4 +1,4 @@
-AIRFLOW__API__AUTH_BACKENDS='airflow.api.auth.backend.basic_auth,airflow.api.auth.backend.session'
+AIRFLOW__API__AUTH_BACKENDS="airflow.api.auth.backend.basic_auth,airflow.api.auth.backend.session"
 AIRFLOW__CELERY__BROKER_URL=redis://:@redis:6379/0
 AIRFLOW__CELERY__RESULT_BACKEND=db+postgresql://airflow:airflow@postgres/airflow
 AIRFLOW__CORE__DAGS_ARE_PAUSED_AT_CREATION=true
diff --git a/init.sh b/init.sh
index 69cd5f8b..35243ad6 100755
--- a/init.sh
+++ b/init.sh
@@ -1,12 +1,12 @@
 #!/bin/bash
 
 function ver() {
-  printf "%04d%04d%04d%04d" ${1//./ }
+  printf "%04d%04d%04d%04d" "${1//./ }"
 }
 airflow_version=$(AIRFLOW__LOGGING__LOGGING_LEVEL=INFO && gosu airflow airflow version)
 airflow_version_comparable=$(ver ${airflow_version})
 min_airflow_version=2.2.0
-min_airflow_version_comparable=$(ver ${min_airflow_version})
+min_airflow_version_comparable=$(ver "${min_airflow_version}")
 if (( airflow_version_comparable < min_airflow_version_comparable )); then
   echo
   echo -e "\033[1;31mERROR!!!: Too old Airflow version ${airflow_version}!\e[0m"