diff --git a/cert-autorefresh b/cert-autorefresh
index 6fd09af5dfa386ecabdb6de0f290dedcd7c375a7..6f1fca5aa53171d5765d680f89c8db72e56c2262 100755
--- a/cert-autorefresh
+++ b/cert-autorefresh
@@ -1,10 +1,23 @@
 #!/usr/bin/env bash
 
+#
+# bash switches
+#
+
+#set -e
+set -u
+set -o pipefail
+#set -x
+
 #
 # constant
 #
 
 apitokenfile=$( basename $0 ).apitoken
+apitoken=""
+verbose=0
+revoke=""
+symlinks=""
 
 #
 # Help
@@ -28,8 +41,6 @@ function helpAndExit()
 # Get Options
 #
 
-verbose=0
-
 while [ "$#" -gt 0 ]; do
     case "$1" in
         -t|--token)
@@ -41,11 +52,11 @@ while [ "$#" -gt 0 ]; do
             shift 2
             ;;
         -r|--revoke)
-            revoke=TRUE
+            revoke=true
             shift 1
             ;;
         -s|--symlinks)
-            symlinks=TRUE
+            symlinks=true
             shift 1
             ;;
         -v|--verbose)
@@ -133,6 +144,8 @@ certListElements=$( echo $content | jq 'length')
 [ $certListElements -gt 2 ] && echo "[ERROR   ] RA-Portal Cert-List contains more than 2 elements." && exit 3
 
 i=0
+expiresAtCert=""
+referenceNumberRenew=""
 while [ $i -lt $certListElements ]
 do
     referenceNumber=$( echo $content | jq -r ".[$i] | .reference_number" )