def remove_environment(environment_var_name, system=False):
    """
    Remove the specified environment setting from the appropriate config file.

    :param environment_var_name: The name of the environment setting to remove.
    :keyword system: Set to True to modify the system configuration file.
                     If not set, the user config file will be modified.
    """
    config_filename = \
        _SYSTEM_CONFIG_FILE if system is True else _USER_CONFIG_FILE
    config = _read_config(config_filename)

    section = _ENVIRONMENT_SECTION_NAME
    config.remove_option(section, environment_var_name)
    _write_config(config, config_filename)