diff --git a/infrastructure-centred/owlps-aggregator/owlps-aggregatord.c b/infrastructure-centred/owlps-aggregator/owlps-aggregatord.c
index e965293..bb5c746 100644
--- a/infrastructure-centred/owlps-aggregator/owlps-aggregatord.c
+++ b/infrastructure-centred/owlps-aggregator/owlps-aggregatord.c
@@ -1105,13 +1105,13 @@ void print_usage()
          "\t%s"
          " [-f config_file]"
          " [-v]"
-         " [-l listening_port]"
+         " [-o output_file]"
          " [-i positionner_ip]"
          " [-p positioner_port]"
+         " [-l listening_port]"
          " [-t aggregate_timeout]"
          " [-k keep_timeout]"
          " [-c check_interval]"
-         " [-o output_file]"
          " [-A]"
          " [-a autocalibration_port]"
          " [-K ap_keep_timeout]"
@@ -1121,19 +1121,21 @@ void print_usage()
          "Main options:\n"
          "\t-h\t\tPrint this help.\n"
          "\t-f config_file\tUse 'config_file' instead of the default"
-         " configuration file.\n"
+         " configuration file (%s).\n"
          "\t-v\t\tBe verbose (print detailed info on each received"
          " message).\n"
 
-         "Server options:\n"
-         "\t-l listening_port\tOnly requests sent on this port will be"
-         " treated (default: %d).\n"
+         "Output options:\n"
+         "\t-o output_file\t\tAggregated requests will be appended to"
+         " this file.\n"
          "\t-i positionner_ip\tIP address of the localisation server"
          " (default: %s).\n"
          "\t-p positioner_port\tAggregated requests are transmitted to"
          " the localisation server on this port (default: %d).\n"
 
          "Aggregation options:\n"
+         "\t-l listening_port\tOnly requests sent on this port will be"
+         " treated (default: %d).\n"
          "\t-t aggregate_timeout\tRequests are stored during"
          " 'aggregate_timeout' milliseconds before to be grouped"
          " (default:  %d ms).\n"
@@ -1152,9 +1154,10 @@ void print_usage()
          " checks of the stored APs (default: %d ms).\n"
          ,
          program_name,
-         AGGREGATE_DEFAULT_PORT,
+         DEFAULT_CONFIG_FILE,
          POSITIONER_DEFAULT_IP,
          POSITIONER_DEFAULT_PORT,
+         AGGREGATE_DEFAULT_PORT,
          DEFAULT_AGGREGATE_TIMEOUT,
          DEFAULT_KEEP_TIMEOUT,
          DEFAULT_CHECK_INTERVAL,