diff --git a/bin/example.rb b/bin/example.rb
index c898258..963ad32 100755
--- a/bin/example.rb
+++ b/bin/example.rb
@@ -1,25 +1,47 @@
 #!/usr/bin/env ruby
 
+require 'pathname'
+$:.unshift Pathname.new(__FILE__).dirname.dirname.join('lib').to_s
 require 'dencli'
 
 cli = DenCli.new 'example', "This is an example for generate a DenCli-API"
 cli.cmd( :example, "I have an example command") { STDERR.puts "This is an example" }
 cli.cmd( :help, "", aliases: [nil, '-h', '--help']) {|*args| STDERR.puts cli.help(*args) }
 
+cli.cmd( :args, "Expects and prints given arguments", &lambda {|a, b, c:, d:, e:|
+		p a: a, b: b, c: c, d: d, e: e
+	}).
+	opt( :c, '-c=ForC', "Option c").
+	opt( :d, '-d=ForD', "Option d", default: "something").
+	opt( :e, '-e', "Toggle e", default: false)
+
 cli.sub( :more, "Sub-Commands are also possible with a new cli") do |sub|
+	sub.cmd( :help, "", aliases: [nil, '-h', '--help']) {|*args| STDERR.puts sub.help(*args) }
 	sub.cmd( :help, "") {|*args| STDERR.puts cli.help( 'more', *args) }
 	sub.cmd( :example, "Here is an example, too") { STDERR.puts "This is an other example" }
 	sub.cmd( :foo, "BAR") { STDERR.puts "FOO bar"}
 
+	sub.cmd( :args, "Expects and prints given arguments", &lambda {|a, b=1, c:, d: 5, e:|
+			p a: a, b: b, c: c, d: d, e: e
+		}).
+		opt( :c, '-c=ForC', "Option c").
+		opt( :d, '-d=ForD', "Option d (implicit default)").
+		opt( :e, '-e', "Toggle e")
+
 	sub.sub( :deeper, "You want to have Sub-Sub-Commands?") do |sub2|
-		sub2.cmd( :help, "") {|*args| STDERR.puts cli.help( 'more', 'deeper', *args) }
-		sub2.cmd( :last, "The last example") { STDERR.puts "The last example" }
+		sub2.cmd( :help, "", aliases: [nil, '-h', '--help'], &lambda {|*args| STDERR.puts sub2.help(*args) })
+		sub2.cmd( :last, "The last example", &lambda { STDERR.puts "The last example" })
 
 		sub2.sub( :'sub-commands', "Endless Sub-Sub- ...") do |sub3|
-			sub2.cmd( :help, "") {|*args| STDERR.puts cli.help( 'more', 'deeper', 'sub-commands', *args) }
+			sub3.cmd( :help, "") {|*args| STDERR.puts sub3.help( sub3, *args) }
 			sub3.cmd( :hehe, "The real last example", min: 2) { STDERR.puts "Trust me!" }
 		end
 	end
 end
 
-cli.call *ARGV
+begin
+	cli.call *ARGV
+rescue DenCli::UsageError
+	STDERR.puts $!
+	exit 1
+end
diff --git a/lib/dencli/cmd.rb b/lib/dencli/cmd.rb
index 8d4dfd6..f7cd0f8 100644
--- a/lib/dencli/cmd.rb
+++ b/lib/dencli/cmd.rb
@@ -1,12 +1,13 @@
 require_relative '../dencli'
 
+
 class DenCli::CMD
 	attr_reader :parent, :name, :description, :exe, :completion, :options
 
 	def initialize parent, name, description, exe
 		raise "Proc expected, instead of: #{exe.inspect}"  unless Proc === exe
 		@parent, @name, @description, @exe = parent, name, description, lambda( &exe)
-		@options = []
+		@options = {}
 		completion {|*a| [] }
 	end
 
@@ -14,59 +15,163 @@ class DenCli::CMD
 	def full_cmd() _full_cmd [] end
 
 	def parameters() @exe.parameters end
-	def required() @exe.parameters.select{|e|:req == e[0]}.map{|e|e[1]} end
-	def additional() @exe.parameters.select{|e|:opt == e[0]}.map{|e|e[1]} end
+	def arguments_required() @exe.parameters.select {|e| :req == e[0] }.map {|e| e[1] } end
+	alias required arguments_required
+	def arguments_additional() @exe.parameters.select {|e| :opt == e[0] }.map {|e| e[1] } end
+	alias additional arguments_additional
+	def arguments() @exe.parameters.select {|e| :req == e[0] or :opt == e[0] }.map {|e| e[1] } end
+	def options_required() @exe.parameters.select {|e| :keyreq == e[0] }.map {|e| e[1] } end
+	def options_additional() @exe.parameters.select {|e| :key == e[0] }.map {|e| e[1] } end
+
+	def help() "Usage: #{usage}\n#{description}\n#{options_help}" end
+	def complete( *pre, str) @completion.call *pre, str end
 
 	def call( *as)
-		if @options.empty?
-			@exe.call *as
-		else
-			os = {}
+		os = {}
+		unless @options.empty?
+			# options like --abc | -x will be provided in os
 			options = OptionParser.new
 			options.banner = "#{full_cmd.join ' '}"
-			@options.each do |(aname, aas, aos, aexe)|
-				os[aname] = aos[aname]  if aos.has_key? :default
-				options.on( *aas) {|val| os[aname] = aexe[val] }
-			end
+			# see also @options-array
+			@options.each {|_, opt| opt.on options, os }
 			as = options.parse! as
-			if @exe.lambda?
-				pars = required
-				if as.length < pars.length
-					raise DenCli::UsageError, "Missing parameter(s): #{pars[as.length..-1].join " "}"
-				end
-				if parameters.select{|e|:rest == e[0]}.empty?
-					pars = pars + additional
-					if as.length > pars.length
-						raise DenCli::UsageError, "Unused parameter(s): #{as[-pars.length..-1].shelljoin}"
-					end
+		end
+		if @exe.lambda?
+			# The difference between a lambda and a Proc is, that Proc has anytime arity=-1.
+			# There will be no check if all arguments are given or some were missing or more than expected.
+			# lambda checks these arguments and has a arity.
+			# We will check it to provide useful errors.
+			pars = required
+			if as.length < pars.length
+				raise DenCli::UsageError, "Missing parameter(s): #{pars[as.length..-1].join " "}"
+			end
+			if parameters.select {|e| :rest == e[0] }.empty?
+				pars = pars + additional
+				if as.length > pars.length
+					raise DenCli::UsageError, "Unused parameter(s): #{as[-pars.length..-1].shelljoin}"
 				end
 			end
-			@exe.call *as, **os
+			kr = @options.select {|_, o| o.required? and not os.has_key? o.name }
+			unless kr.empty?
+				raise DenCli::UsageError, "Missing argument(s): #{kr.map {|o| o.as.first }.join ', '}"
+			end
 		end
+		@exe.call *as, **os
 	end
 
 	def usage
-		"#{parent.full_cmd.join ' '} #{name} "+
-			@options.map{|(_,(o,_,_,_),_)|"[#{o}] "}.join( '')+
+		args =
+			@options.map do |_, o|
+				s = "#{o.short}#{o.val ? ?= : ''}#{o.val}"; o.required? ? "#{s} " : "[#{s}] "
+			end
+		"#{full_cmd.join ' '}  #{args.join ''}"+
 			(@exe.lambda? ? (
-				required.join( " ")+
-				(additional.empty? ? "" : " [#{additional.join " "}]")
+				required.map{|s|"<#{s}>"}.join( " ")+
+				(additional.empty? ? "" : " [#{additional.map{|s|"<#{s}>"}.join " "}]")
 			) : '...')
 	end
 
-	def help
-		"#{usage}\n#{description}"
+	def options_help
+		sc, lc, dc = 0, 0, 0
+		@options.each do |_, o|
+			s = o.short&.length || 0
+			l = o.long&.length || 0
+			v = o.val&.length || 0
+			d = o.desc&.to_s&.length || 0
+			d += 3 + o.default.to_s.length  if o.default?
+			if 0 == l
+				x = s + (0==v ? 0 : 1+v)
+				sc = x  if sc < x
+			else
+				sc = s  if sc < s
+				x = l + (0==v ? 0 : 1+v)
+				lc = x  if lc < x
+			end
+			dc = d  if dc < d
+		end
+		format = "  %-#{sc}s%s %-#{lc}s %s"
+		@options.map {|_, o|
+			s, l, v, y = o.short, o.long, o.val, ','
+			if l.nil?
+				s += "=#{v}"  if v
+				y = ' '
+			elsif s.nil?
+				l += "=#{v}"  if v
+				y = ' '
+			end
+			d = o.desc || ''
+			d += " (#{o.default})"  if o.default?
+			format % [ s, y, l, d ]
+		}.join "\n"
 	end
 
-	def complete( *pre, str) @completion.call *pre, str end
-
 	def completion &exe
 		@completion = exe
 		self
 	end
 
-	def opt name, *as, **os, &exe
-		@options.push [name.to_s.to_sym, as, os, exe || lambda{|val|val} ]
+	class Opt
+		attr_reader :name, :long, :short, :val, :desc, :os, :conv, :req
+		def required?() @req end
+		def default?() NilClass != @default end
+		def default() NilClass == @default ? nil : @default end
+
+		def initialize cmd, name, opt, *alts, desc, default: NilClass, **os, &conv
+			long = short = val = nil
+			case opt
+			when /\A(--[^=-]+)=(.+)\z/
+				long, val = $1, $2
+			when /\A(--[^=-]+)\z/
+				long, val = $1, nil
+			when /\A(-[^=-]+)=(.+)\z/
+				short, val = $1, $2
+			when /\A(-[^=-]+)\z/
+				short, val = $1, nil
+			else raise ArgumentError, "Unexpected format for option: #{opt.inspect}"
+			end
+			alts.each do |alt|
+				case alt
+				when /\A(--[^=-]+)=(.+)\z/
+					long, val = $1, val || $2
+				when /\A(--[^=-]+)\z/
+					long, val = $1, nil
+				when /\A(-[^=-]+)=(.+)\z/
+					short, val = $1, val || $2
+				when /\A(-[^=-]+)\z/
+					short, val = $1, nil
+				else raise ArgumentError, "Unexpected format for option: #{alt.inspect}"
+				end
+			end
+			@name, @short, @long, @val, @desc, @default, @os, @conv =
+				name.to_s.to_sym, short, long, val, desc, default, os, conv || lambda{|v|v}
+			@req =
+				if NilClass != default
+					false
+				elsif cmd.exe.lambda?
+					! cmd.exe.parameters.select {|e| [:keyreq, @name] == e[0..1] }.empty?
+				else
+					nil
+				end
+		end
+
+		def on parser, store
+			parser.on "#{@short}#{@val ? ?= : ''}#{@val}", "#{@long}#{@val ? ?= : ''}#{@val}", **@os do |val|
+				store[@name] = @conv[val]
+			end
+		end
+
+		def inspect
+			"#<%s:0x%016x %s %s %s %s (%p) %p os=%p conv=%s>" % [
+				self.class.name, object_id, @req ? "<#{@name}>" : "[#{@name}]",
+				@short, @long, @val, @default, @desc, @os,
+				@exe ? "<#{@exe.lambda? ? :lambda: :proc} ##{@exe.arity}>" : "nil"
+			]
+		end
+	end
+
+	def opt name, opt, *alts, desc, **os, &conv
+		r = Opt.new( self, name, opt, *alts, desc, **os, &conv)
+		@options[r.name] = r
 		self
 	end
 
diff --git a/lib/dencli/version.rb b/lib/dencli/version.rb
index ad7110b..1d939af 100644
--- a/lib/dencli/version.rb
+++ b/lib/dencli/version.rb
@@ -1,3 +1,3 @@
 class DenCli
-	VERSION = '0.3.2'
+	VERSION = '0.4.0'
 end