protected String expandProperties(final String input) {
    String output = input;
    Scanner s = new Scanner(output);
    String foundInLine;
    while ((foundInLine = s.findInLine("(\\$[\\{]\\w+[\\}])")) != null) {
      String envProperty = getEnvProperty(extractKey(foundInLine));
      envProperty = envProperty != null ? envProperty : "";
      output = output.replace(foundInLine, envProperty);
    }
    return output;
  }
@param operationInvoker the operationInvoker to set
geode-gfsh/src/main/java/org/apache/geode/management/internal/cli/shell/Gfsh.java