diff --git a/src/cli.js b/src/cli.js
index 90e7489..5d766a9 100755
--- a/src/cli.js
+++ b/src/cli.js
@@ -44,21 +44,21 @@ function main(program) {
 if (require.main === module) {
     program
         .version(packageJson.version)
-        .arguments('<targetUrl> [appDir]')
+        .arguments('<targetUrl> [dest]')
         .action(function (targetUrl, appDir) {
             program.targetUrl = targetUrl;
             program.outDir = appDir;
         })
-        .option('-n, --appName [value]', 'app name')
-        .option('-p, --platform [platform]', '\'linux\', \'win32\', or \'darwin\'')
-        .option('-a, --arch [architecture]', '\'ia32\' or \'x64\'')
-        .option('-e, --electron-version', 'electron version to package, without the \'v\', see https://github.com/atom/electron/releases')
-        .option('-o, --overwrite', 'if output directory for a platform already exists, replaces it rather than skipping it, defaults to true')
+        .option('-n, --app-name <value>', 'app name')
+        .option('-p, --platform <value>', '\'linux\', \'win32\', or \'darwin\'')
+        .option('-a, --arch <value>', '\'ia32\' or \'x64\'')
+        .option('-e, --electron-version <value>', 'electron version to package, without the \'v\', see https://github.com/atom/electron/releases')
+        .option('-o, --overwrite', 'if output directory for a platform already exists, replaces it rather than skipping it, defaults to false')
         .option('-c, --conceal', 'packages the source code within your app into an archive, defaults to false, see http://electron.atom.io/docs/v0.36.0/tutorial/application-packaging/')
-        .option('-i, --icon [dir]', 'the icon file to use as the icon for the app (should be a .icns file on OSX)')
         .option('-b, --badge', 'if the target app should show badges in the dock on receipt of desktop notifications (OSX only), defaults to false')
-        .option('-w, --width [value]', 'set window width, defaults to 1280px')
-        .option('-h, --height [value]', 'set window height, defaults to 800px')
+        .option('-i, --icon <value>', 'the icon file to use as the icon for the app (should be a .icns file on OSX)')
+        .option('-w, --width <value>', 'set window width, defaults to 1280px', parseInt)
+        .option('-h, --height <value>', 'set window height, defaults to 800px', parseInt)
         .parse(process.argv);
 
     if (!process.argv.slice(2).length) {
diff --git a/src/options.js b/src/options.js
index a843ea2..a36db8c 100644
--- a/src/options.js
+++ b/src/options.js
@@ -15,7 +15,7 @@ function optionsFactory(name,
                         arch = detectArch(),
                         version = ELECTRON_VERSION,
                         outDir = process.cwd(),
-                        overwrite = true,
+                        overwrite = false,
                         conceal = false,
                         icon,
                         badge = false,
@@ -23,7 +23,15 @@ function optionsFactory(name,
                         height = 800, callback) {
 
     if (!validator.isURL(targetUrl, {require_protocol: true})) {
-        throw 'Your Url is invalid!, did you remember to include \'http://\'?';
+        throw `Your Url ${targetUrl} is invalid!, did you remember to include 'http://'?`;
+    }
+
+    if (!width) {
+        width = 1280;
+    }
+
+    if (!height) {
+        height = 800;
     }
 
     const options = {