diff --git a/HowtoNagiosChecksWrapper.md b/HowtoNagiosChecksWrapper.md
index c78b2aff..c47feec5 100644
--- a/HowtoNagiosChecksWrapper.md
+++ b/HowtoNagiosChecksWrapper.md
@@ -127,15 +127,15 @@ Détail du script `alerts_wrapper` :
 ~~~{.bash}
 #!/bin/bash
 
-check_file="/tmp/$1_alerts_disabled"
+readonly check_file="/tmp/$1_alerts_disabled"
 shift
 
-check_stdout=$($@)
-check_rc=$?
+readonly check_stdout=$($@)
+readonly check_rc=$?
 
 if [ -e "${check_file}" ]; then
-    last_change=$(stat -c %Z "${check_file}")
-    limit=$(date --date '24 hours ago' +'%s')
+    local last_change=$(stat -c %Z "${check_file}")
+    local limit=$(date --date '24 hours ago' +'%s')
 
     if [ ${last_change} -le ${limit} ]; then
         rm "${check_file}"
@@ -143,7 +143,7 @@ if [ -e "${check_file}" ]; then
 fi
 
 if [ -e "${check_file}" ]; then
-    formatted_last_change=$(date --date "@$(stat -c %Z "${check_file}")" +'%c')
+    local formatted_last_change=$(date --date "@$(stat -c %Z "${check_file}")" +'%c')
 
     echo "ALERTS DISABLED (since ${formatted_last_change}) - ${check_stdout}"
     if [ ${check_rc} = 0 ]; then