title: Getting error message while starting appium
body: <p>After start the appium server. I got this message. Kindly tell what went wrong
  usage: main.js [-h] [-v] [--shell]</p>
  
  <blockquote>
  <pre><code>           [--localizable-strings-dir LOCALIZABLESTRINGSDIR] [--app APP]
             [--ipa IPA] [-q] [-U UDID] [-a ADDRESS] [-p PORT]
             [-bp BOOTSTRAPPORT] [-k] [-r BACKENDRETRIES]
             [--session-override] [--full-reset] [--no-reset] [-l]
             [-lt LAUNCHTIMEOUT] [-g LOG]
             [--log-level {debug,info,warn,error}] [--log-timestamp]
             [--log-no-colors] [-G WEBHOOK] [--native-instruments-lib]
             [--app-pkg ANDROIDPACKAGE] [--app-activity ANDROIDACTIVITY]
             [--app-wait-package ANDROIDWAITPACKAGE]
             [--app-wait-activity ANDROIDWAITACTIVITY]
             [--android-coverage ANDROIDCOVERAGE] [--avd AVD]
             [--avd-args AVDARGS]
             [--device-ready-timeout ANDROIDDEVICEREADYTIMEOUT] [--safari]
             [--device-name DEVICENAME] [--platform-name PLATFORMNAME]
             [--platform-version PLATFORMVERSION]
  </code></pre>
    
    <p>main.js: error: argument "--app": Expected one argument. null</p>
  </blockquote>