Update README.md

README.md

@@ -1,2 +1,15 @@
 # labcalcoloctl
 Simple tool to handle LabCalcolo's VMs.
+
+usage: labcalcolo [{status,start,stop}] [options]
+
+positional arguments:
+  {status,start,stop}  Specify command to execute, default is 'status'
+
+optional arguments:
+  -h, --help           show this help message and exit
+  -a, --all            All LCM nodes are considered
+  -n NODE [NODE ...]   Select one or more nodes (at least one)
+  -1, --lcm1           LCM1 nodes are considered
+  -2, --lcm2           LCM2 nodes are considered
+  -v, --version        Print program version