diff --git a/postgres-backup/app/entrypoint.sh b/postgres-backup/app/entrypoint.sh
index 9e236ae..c466eb9 100644
--- a/postgres-backup/app/entrypoint.sh
+++ b/postgres-backup/app/entrypoint.sh
@@ -1,5 +1,6 @@
 #!/bin/bash
 
+# shellcheck source=/dev/null
 . /app/includes.sh
 
 # restore
@@ -14,7 +15,8 @@ if [[ "$1" == "restore" ]]; then
 fi
 
 function configure_cron() {
-  local FIND_CRON_COUNT="$(grep -c 'backup.sh' "${CRON_CONFIG_FILE}" 2> /dev/null)"
+  local FIND_CRON_COUNT
+  FIND_CRON_COUNT="$(grep -c 'backup.sh' "${CRON_CONFIG_FILE}" 2> /dev/null)"
   if [[ "${FIND_CRON_COUNT}" -eq 0 ]]; then
     echo "${CRON} bash /app/backup.sh" >> "${CRON_CONFIG_FILE}"
   fi