+ Update readme

centreon-plugins/README.md

@@ -1,4 +1,71 @@
 # centreon-plugins
 “centreon-plugins” is a free and open source project to monitor systems. The project can be used with Centreon and all monitoring softwares compatible with Nagios plugins.
 
+You can monitor many systems:
+* application: Apache, Nginx, Tomcat, Pfsense, ...
+* database: Informix, MySQL, Postgres, Oracle, MS SQL
+* hardware: printers (rfc3805), UPS (Powerware, Mge, Standard), Sun Hardware, Cisco UCS, SensorIP, HP Proliant, HP Bladechassis, Dell Openmanage, Dell CMC, 
+* network: Aruba, Brocade, Bluecoat, Brocade, Checkpoint, Cisco AP/IronPort/ASA/Standard, Extreme, Fortigate, H3C, Hirschmann, HP Procurve, F5 BIG-IP, Juniper, PaloAlto, Redback, Riverbed, Ruggedcom, Stonesoft,...
+* os: Linux (SNMP, NRPE), Freebsd (SNMP), AIX (SNMP), Solaris (SNMP)...
+* storage: EMC Clariion, Netapp, HP MSA p2000, Dell EqualLogic, Qnap, Panzura, Synology...
+
+## Basic Usage
+
+We'll use a basic example to show you how to monitor a system. I have finished the install section and i want to monitor a Linux in SNMP.
+First, i need to find the plugin to use in the list:
+
+    $ perl centreon_plugins.pl --list-plugin | grep -i linux | grep 'PLUGIN'
+    PLUGIN: os::linux::local::plugin
+    PLUGIN: os::linux::snmp::plugin
+
+It seems that 'os::linux::snmp::plugin' is the good one. So i verify with the option ``--help`` to be sure:
+
+    $ perl centreon_plugins.pl --plugin=os::linux::snmp::plugin --help
+    ...
+    Plugin Description:
+      Check Linux operating systems in SNMP.
+
+It's exactly what i need. Now i'll the option ``--list-mode`` to know what can i do with it:
+
+    $ perl centreon_plugins.pl --plugin=os::linux::snmp::plugin --list-mode
+    ...
+    Modes Available:
+     processcount
+     time
+     list-storages
+     disk-usage
+     diskio
+     uptime
+     swap
+     cpu-detailed
+     load
+     traffic
+     cpu
+     inodes
+     list-diskspath
+     list-interfaces
+     packet-errors
+     memory
+     tcpcon
+     storage
+
+I would like to test the 'load' mode:
+
+    $ perl centreon_plugins.pl --plugin=os::linux::snmp::plugin --mode=load
+    UNKNOWN: Missing parameter --hostname.
+
+It's not working because some options are missing. I can have a description of the mode and options with the option ``--help``:
+
+    $ perl centreon_plugins.pl --plugin=os::linux::snmp::plugin --mode=load --help
+
+Eventually, i have to configure some SNMP options:
+
+    $ perl centreon_plugins.pl --plugin=os::linux::snmp::plugin --mode=load --hostname=127.0.0.1 --snmp-version=2c --snmp-community=public
+    OK: Load average: 0.00, 0.00, 0.00 | 'load1'=0.00;;;0; 'load5'=0.00;;;0; 'load15'=0.00;;;0;
+
+I can set threshold with options ``--warning`` and ``--critical``:
+
+    $ perl centreon_plugins.pl --plugin=os::linux::snmp::plugin --mode=load --hostname=127.0.0.1 --snmp-version=2c --snmp-community=public --warning=1,2,3 --critical=2,3,4
+    OK: Load average: 0.00, 0.00, 0.00 | 'load1'=0.00;0:1;0:2;0; 'load5'=0.00;0:2;0:3;0; 'load15'=0.00;0:3;0:4;0;
+
 For more information or help, please read 'docs/user/guide.rst' or go to http://documentation.centreon.com/docs/centreon-plugins/en/latest/