Implement logs -n/--num

lib/actions/logs.coffee

@@ -19,8 +19,18 @@ exports.logs = (uuid) ->
 
 		channel = "device-#{uuid}-logs"
 
+		numberOfLines = resin.cli.getArgument('num', _.parseInt)
+		if numberOfLines? and not _.isNumber(numberOfLines)
+			resin.errors.handle(new Error('n/num should be a number'))
+
 		printLogs = (logs) ->
 			logs = logs[0] if _.isArray(logs)
+
+			if numberOfLines?
+				logs = _.last(logs, numberOfLines)
+				resin.log.array(logs, resin.log.out)
+				process.exit(0)
+
 			resin.log.array(logs, resin.log.out)
 
 		pubnub.history
@@ -28,6 +38,7 @@ exports.logs = (uuid) ->
 			channel: channel
 			callback: printLogs
 
+		if not numberOfLines?
 			pubnub.subscribe
 				channel: channel
 				callback: printLogs

lib/app.coffee

@@ -23,6 +23,10 @@ resin.cli.addOption
 	option: '-t, --type <type>'
 	description: 'specify a type when creating an application'
 
+resin.cli.addOption
+	option: '-n, --num <num>'
+	description: 'number of lines to display'
+
 # TODO: I have to use 'application' instead of 'app' here
 # as Commander gets confused with the app command
 resin.cli.addOption

lib/resin/cli/cli.coffee

@@ -6,8 +6,17 @@ log = require('../log/log')
 errors = require('../errors/errors')
 cliPermissions = require('./cli-permissions')
 
-exports.getArgument = (name) ->
-	return program[name]
+exports.getArgument = (name, coerceFunction) ->
+	argument = program[name]
+	return if not argument?
+
+	if _.isFunction(coerceFunction)
+		argument = coerceFunction(argument)
+
+	if not argument? or _.isNaN(argument)
+		throw new Error('Coerce function failed')
+
+	return argument
 
 exports.setVersion = (version) ->
 	program.version(version)