Ruby for Meterpreter

As i found out to write a meterpreter script i need ruby programming language. I seacrhed on the internet and i got to offensive-security site , title custom scripting. I tried out there examples and i got errors, the say to print the comand is print_status("Hello World") but on another site i found that the comand is print "Hello World", the last one worked but on that site they didn't have things that you use in meterpreter so if you know a tutorial about rubby in meterpreter please tell me