variables = new HashMap();
out = new Output();
out.addChannel(new ConsoleOutputChannel());
rootCommand = new RootCommand(out);
/*add the root_command object to HashMap so that
commands such as + and - can access it to invoke hexdump command*/
variables.put(Utils.RootCommand_OBJECT, rootCommand);
variables.put("pwd", new File(System.getProperty("user.dir")));