code: @Then("^I modify marathon environment variable '(.+?)' with value '(.+?)' for service '(.+?)'?$")
      public void setMarathonProperty(String key, String value, String service) throws Exception {
          commonspec.runCommandAndGetResult("touch " + service + "-env.json && dcos marathon app show " + service + " > /dcos/" + service + "-env.json");
          commonspec.runCommandAndGetResult("cat /dcos/" + service + "-env.json");
  
          String configFile = commonspec.getRemoteSSHConnection().getResult();
          String myJson1 = commonspec.replaceJSONPathElement(configFile, key, value);
          String myJson4 = commonspec.updateMarathonJson(myJson1);
          String myJson = myJson4.replaceAll("\"uris\"", "\"none\"");
  
          commonspec.runCommandAndGetResult("echo '" + myJson + "' > /dcos/final" + service + "-env.json");
          commonspec.runCommandAndGetResult("dcos marathon app update " + service + " < /dcos/final" + service + "-env.json");
          commonspec.setCommandExitStatus(commonspec.getRemoteSSHConnection().getExitStatus());
      }
docs: Set a environment variable in marathon and deploy again.
  
  @param key
  @param value
  @param service
  @throws Exception