diff --git a/extra/alerts/alert_file.sh.sample b/extra/alerts/alert_file.sh.sample
index 0a9ee76bdd..cccff7c9ea 100644
--- a/extra/alerts/alert_file.sh.sample
+++ b/extra/alerts/alert_file.sh.sample
@@ -1,102 +1,102 @@
 #!/bin/sh
 #
 # Copyright (C) 2015 Andrew Beekhof <andrew@beekhof.net>
 #
 # This program is free software; you can redistribute it and/or
 # modify it under the terms of the GNU General Public
 # License as published by the Free Software Foundation; either
 # version 2 of the License, or (at your option) any later version.
 #
 # This software is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 # General Public License for more details.
 #
 # You should have received a copy of the GNU General Public
 # License along with this library; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 #
 ##############################################################################
 # Sample configuration (cib fragment in xml notation)
 # ================================
 # <configuration>
 #   <alerts>
 #     <alert id="alert_sample" path="/path/to/alert_file.sh">
 #       <instance_attributes id="config_for_alert_file">
 #         <nvpair id="debug_option_1" name="debug_exec_order" value="false"/>
 #       </instance_attributes>
 #       <meta_attributes id="config_for_timestamp">
 #         <nvpair id="ts_fmt" name="timestamp-format" value="%H:%M:%S.%06N"/>
 #       </meta_attributes>
 #       <recipient id="logfile_destination" value="/path/to/logfile"/>
 #     </alert>
 #   </alerts>
 # </configuration>
 
 if [ -z $CRM_alert_version ]; then
     echo "Pacemaker version 1.1.15 or later is required" >> "${CRM_alert_recipient}"
     exit 0
 fi
 
 debug_exec_order_default="false"
 
 # Pacemaker passes instance attributes to alert agents as environment variables.
 # It is completely up to the agent what instance attributes to support.
 # Here, we define an instance attribute "debug_exec_order".
 : ${debug_exec_order=${debug_exec_order_default}}
 
 if [ "${debug_exec_order}" = "true" ]; then
     tstamp=`printf "%04d. " "$CRM_alert_node_sequence"`
-    if [ ! -z $CRM_alert_timestamp ]; then
+    if [ ! -z "$CRM_alert_timestamp" ]; then
         tstamp="${tstamp} $CRM_alert_timestamp (`date "+%H:%M:%S.%06N"`): "
     fi
 else
-    if [ ! -z $CRM_alert_timestamp ]; then
+    if [ ! -z "$CRM_alert_timestamp" ]; then
         tstamp="$CRM_alert_timestamp: "
     fi
 fi
 
 case $CRM_alert_kind in
     node)
         echo "${tstamp}Node '${CRM_alert_node}' is now '${CRM_alert_desc}'" >> "${CRM_alert_recipient}"
         ;;
     fencing)
         # Other keys:
         #
         # CRM_alert_node
         # CRM_alert_task
         # CRM_alert_rc
         #
         echo "${tstamp}Fencing ${CRM_alert_desc}" >> "${CRM_alert_recipient}"
         ;;
     resource)
         # Other keys:
         #
         # CRM_alert_target_rc
         # CRM_alert_status
         # CRM_alert_rc
         #
         if [ ${CRM_alert_interval} = "0" ]; then
             CRM_alert_interval=""
         else
             CRM_alert_interval=" (${CRM_alert_interval})"
         fi
 
         if [ ${CRM_alert_target_rc} = "0" ]; then
             CRM_alert_target_rc=""
         else
             CRM_alert_target_rc=" (target: ${CRM_alert_target_rc})"
         fi
 
         case ${CRM_alert_desc} in
             Cancelled) ;;
             *)
                 echo "${tstamp}Resource operation '${CRM_alert_task}${CRM_alert_interval}' for '${CRM_alert_rsc}' on '${CRM_alert_node}': ${CRM_alert_desc}${CRM_alert_target_rc}" >> "${CRM_alert_recipient}"
                 ;;
         esac
         ;;
     *)
         echo "${tstamp}Unhandled $CRM_alert_kind alert" >> "${CRM_alert_recipient}"
         env | grep CRM_alert >> "${CRM_alert_recipient}"
         ;;
 esac