diff --git a/README.md b/README.md
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@@ -1,6 +1,10 @@
 # cellular-automaton
 This is an implementation of 256 elementary cellular automatons: http://mathworld.wolfram.com/ElementaryCellularAutomaton.html
 
+Usage:
+```
+./cellaut.pl <number of generations> <width> <rule number (0-255)> [num rules]
+```
 Example usage and output for rule 30:
 ```
 ./cellaut.pl 10 30 30