Reading text from standard input can be done as follows:

    try {
            
            BufferedReader in = new BufferedReader(
                    new InputStreamReader(System.in));
            
            String str = "";
            
            while (str != null) {
            
                System.out.print("$bash> ");
                str = in.readLine();
                process(str);
                
            }
            
        } catch (IOException e) {
        }