diff --git a/lib/sinatra/main.rb b/lib/sinatra/main.rb
index 5b14442dd9..4b6e271b57 100644
--- a/lib/sinatra/main.rb
+++ b/lib/sinatra/main.rb
@@ -1,6 +1,25 @@
-require 'sinatra/base'
-
 module Sinatra
+  ParamsConfig = {}
+
+  if ARGV.any?
+    require 'optparse'
+    OptionParser.new { |op|
+      op.on('-p port',   'set the port (default is 4567)')                { |val| ParamsConfig[:port] = Integer(val) }
+      op.on('-s server', 'specify rack server/handler (default is thin)') { |val| ParamsConfig[:server] = val }
+      op.on('-q',        'turn on quiet mode (default is off)')           {       ParamsConfig[:quiet] = true }
+      op.on('-x',        'turn on the mutex lock (default is off)')       {       ParamsConfig[:lock] = true }
+      op.on('-e env',    'set the environment (default is development)')  do |val|
+        ENV['RACK_ENV'] = val
+        ParamsConfig[:environment] = val.to_sym
+      end
+      op.on('-o addr', "set the host (default is (env == 'development' ? 'localhost' : '0.0.0.0'))") do |val|
+        ParamsConfig[:bind] = val
+      end
+    }.parse!(ARGV.dup)
+  end
+
+  require 'sinatra/base'
+
   class Application < Base
 
     # we assume that the first file that requires 'sinatra' is the
@@ -10,19 +29,10 @@ class Application < Base
 
     set :run, Proc.new { File.expand_path($0) == File.expand_path(app_file) }
 
-    if run? && ARGV.any?
-      require 'optparse'
-      OptionParser.new { |op|
-        op.on('-p port',   'set the port (default is 4567)')                { |val| set :port, Integer(val) }
-        op.on('-o addr',   "set the host (default is #{bind})")             { |val| set :bind, val }
-        op.on('-e env',    'set the environment (default is development)')  { |val| set :environment, val.to_sym }
-        op.on('-s server', 'specify rack server/handler (default is thin)') { |val| set :server, val }
-        op.on('-q',        'turn on quiet mode (default is off)')           {       set :quiet, true }
-        op.on('-x',        'turn on the mutex lock (default is off)')       {       set :lock, true }
-      }.parse!(ARGV.dup)
-    end
+    ParamsConfig.each { |k, v| set k, v } if run? && ARGV.any?
   end
 
+  remove_const(:ParamsConfig)
   at_exit { Application.run! if $!.nil? && Application.run? }
 end