'This is the method that is called when a user wants to execute something
in the shell.
It is called from shell.generic_user_input() which provides generic
commands like "help".
:param command: The string representing the command that the user
types in the shell.
:param parameters: A list with the parameters for @command'

def specific_user_input(self, command, parameters, return_err=True):

    if (command == 'read'):
        if (len(parameters) == 1):
            filename = parameters[0]
            return self.read(filename)
        else:
            return 'Only    one    parameter    is    expected.    Usage    examples:    "read    /etc/passwd",    "read    \'/var/foo    bar/spam.eggs\'"'
    elif ((command == 'download') and (len(parameters) == 2)):
        remote_filename = parameters[0]
        local_filename = parameters[1]
        return self.download(remote_filename, local_filename)
    elif return_err:
        return ('Command    "%s"    not    found.    Please    type    "help".' % command)
    return
