title: Port 4444 is busy, please choose a free port and specify it using -port option
body: <p>i install protractor using this command: </p>
  
  <blockquote>
    <p>npm install -g protractor,</p>
    
    <p>webdriver-manager update,</p>
    
    <p>webdriver-manager start,</p>
  </blockquote>
  
  <p>after installing this webdriver manager was running fine. then for some reason i thought i need selenium server standalone. so i install it using this command:</p>
  
  <blockquote>
    <p>npm install selenium-standalone@latest -g selenium-standalone install
    selenium-standalone start</p>
  </blockquote>
  
  <p>Now if I run any one of either webdriver-manager start or selenium -standalone start I get these error. I am not running both at the same time. </p>
  
  <pre><code>I/start - java -Dwebdriver.chrome.driver=/usr/local/lib/node_modules/protractor/node_modules/webdriver-manager/selenium/chromedriver_2.41 -Dwebdriver.gecko.driver=/usr/local/lib/node_modules/protractor/node_modules/webdriver-manager/selenium/geckodriver-v0.21.0 -jar /usr/local/lib/node_modules/protractor/node_modules/webdriver-manager/selenium/selenium-server-standalone-3.13.0.jar -port 4444
  [10:17:56] I/start - seleniumProcess.pid: 39645
  10:17:57.250 INFO [GridLauncherV3.launch] - Selenium build info: version: '3.13.0', revision: '2f0d292'
  10:17:57.251 INFO [GridLauncherV3$1.launch] - Launching a standalone Selenium Server on port 4444
  2018-08-02 10:17:57.408:INFO::main: Logging initialized @612ms to org.seleniumhq.jetty9.util.log.StdErrLog
  10:17:57.589 ERROR [SeleniumServer.boot] - Port 4444 is busy, please choose a free port and specify it using -port option
  [10:17:57] I/start - Selenium Standalone has exited with code 0.
  </code></pre>
  
  <p>if anyone knows the reason please let me know. </p>