diff --git a/home/bin/deboco b/home/bin/deboco
index 710f03e..6a402fb 100755
--- a/home/bin/deboco
+++ b/home/bin/deboco
@@ -471,7 +471,7 @@ deboco__init_machine()
 	return "$error_code"
 }
 
-common_update_machine()
+apply_playbook_to_machine()
 {
 	local debops_controller_path="$1"
 	local target_host_fqdn="$2"  # eg alambix-108.ipr.univ-rennes.fr
@@ -511,10 +511,14 @@ common_update_machine()
 		# example to apply just the role rsyslog:
 		if [ "$only_role" != '' ]
 		then
-			unbuffer debops run "${playbook}" --limit "${ANS_HOST:-/dev/null}" -t "${only_role}" | tee --append ${report_file_path}
+			log 'debug' "executing command: [unbuffer debops run "${playbook}" --limit "${ANS_HOST:-/dev/null}" -t "${only_role}" --diff | tee --append ${report_file_path}]..."
+
+			unbuffer debops run "${playbook}" --limit "${ANS_HOST:-/dev/null}" -t "${only_role}" --diff | tee --append ${report_file_path}
 			debops_exit_code=$?
 		else
-			unbuffer debops run "${playbook}" --limit "${ANS_HOST:-/dev/null}" | tee --append ${report_file_path}
+			log 'debug' "executing command: [unbuffer debops run "${playbook}" --limit "${ANS_HOST:-/dev/null}" --diff | tee --append ${report_file_path}]..."
+
+			unbuffer debops run "${playbook}" --limit "${ANS_HOST:-/dev/null}" --diff | tee --append ${report_file_path}
 			debops_exit_code=$?
 		fi
 		echo "return code for debops run site --limit ${ANS_HOST:-/dev/null} : $debops_exit_code" >> "${report_file_path}"
@@ -537,7 +541,7 @@ deboco__update_machine()
 	local target_host_fqdn="$2"  # eg alambix-108.ipr.univ-rennes.fr
 	local only_role=""
 	local playbook="site"
-	common_update_machine "$debops_controller_path" "$target_host_fqdn" "$only_role" "$playbook"
+	apply_playbook_to_machine "$debops_controller_path" "$target_host_fqdn" "$only_role" "$playbook"
 }
 
 deboco__update_machine_partially()
@@ -550,7 +554,7 @@ deboco__update_machine_partially()
 	then
 		playbook='site'
 	fi
-	common_update_machine "$debops_controller_path" "$target_host_fqdn" "$only_role" "$playbook"
+	apply_playbook_to_machine "$debops_controller_path" "$target_host_fqdn" "$only_role" "$playbook"
 }
 
 deboco_print_usage()
@@ -587,7 +591,10 @@ deboco_print_usage()
 	echo "examples:"
 	echo "     deboco --python-path /usr/bin/python3.10 init ~/work/debops/controllers/alambix"
 	echo 
-	echo "example to update xymon server's configuration (here it's much faster to specify the service apache than an unspecified service: 16s instead of 3m 33s):"
+	echo "example to update xymon server's configuration:"
+	echo "     deboco update_machine_partially ~/debops/controllers/alambix monitoring.ipr.univ-rennes.fr role::xymon_server"
+	echo 
+	echo "example to update xymon server's configuration after manually changing xymon server files(here it's much faster to specify the service apache than an unspecified service: 16s instead of 3m 33s):"
 	echo "     deboco update_machine_partially ~/debops/controllers/alambix monitoring.ipr.univ-rennes.fr role::xymon_server service/apache"
 	echo 
 	echo "example to update xymon client's configuration on alambix50 (the playbook that uses the role xymon (ie xymon client)) is currently ipr.post.debops):"