Multiple commands with different options using yargs/optimist

I'm trying to write a CLI for a node module using yargs but I'm having difficulty setting two different commands that could be used, one requiring only one parameter, but the other requiring two. Here is what I have so far ``` var argv = require('yargs') .option('r', { alias : 'reset', describe: 'clear data for site(s)', type: 'string' }). option('d', { alias : 'dashboard', describe: 'copy dashboard for the specified site across all others', type: 'array' }) .usage('Usage: $0 -r [string] -d [array]') .argv; ``` To reset data I would do ``` node main.js -r mysite ``` But to copy a dashboard I want to be to do ``` node main.js -d theSiteToCopyFrom theSiteToCopyTo ``` or even ``` node main.js -d theSiteToCopyFrom [theArrayOfSitesToCopyTo, , ,] ``` I have looked through the examples given, such as ``` var argv = require('yargs') .option('f', { alias : 'file', demand: true, default: '/etc/passwd', describe: 'x marks the spot', type: 'string' }) .argv ; ``` but I can't see how to specify that multiple parameters are required for different commands.