public String cd (String path){
        //checks whether the directory available or not then return it

        File file = new File(path);

        File fileSameDir = new File(Dd+path);

        if (path.equals( "...")){

            int counter = 0;
            int index = Dd.length();
            boolean found = false;

            for (int i = 0; i < Dd.length(); i++) {

                if ((Dd.charAt(i)=='\\' || Dd.charAt(i) == '/')){
                    found = true;
                }

                else if (found){
                    index = i-1;
                    found = false;
                }

            }
            System.out.println("Directory changed to "+obj.printWarning(Dd.substring(0,index+1)));
            return Dd.substring(0,index+1);
        }

        if (path.toLowerCase().equals("desktop")){

            System.out.println("Directory changed to " + obj.printWarning("Desktop"));

            return (System.getProperty("user.home") + "\\Desktop"+"\\");
        }

        if (fileSameDir.exists()){

            System.out.println("Directory changed to " + obj.printWarning(path));

            return (Dd+path+'\\');

        } else if (file.exists()){

            System.out.println("Directory changed to " + obj.printWarning(path));

            return path+"\\";

        }else if (path.equals("~")){

            System.out.println("Directory changed to " + obj.printWarning(path));
            Dd = System.getProperty("user.home")+'\\';
            return System.getProperty("user.home")+'\\';
        }
        else{
            System.out.println(obj.printError("Path may not be available use -mkdir- command to create directory"));
            return Dd;
        }

    }