'Execute a template command in a shell.  If the value of initial_download is True, the recipe steps
will be filtered and returned and the installation directory (i.e., dir) will be defined and returned.
If we\'re not in the initial download stage, these actions will not occur, and None values will be
returned for them.'

def execute_step(self, tool_dependency, package_name, actions, action_dict, filtered_actions, env_file_builder, install_environment, work_dir, current_dir=None, initial_download=False):

    env_vars = dict()
    env_vars = install_environment.environment_dict()
    env_vars.update(basic_util.get_env_var_values(install_environment))
    language = action_dict['language']
    with settings(warn_only=True, **env_vars):
        if (language == 'cheetah'):
            cmd = fill_template(('#from    fabric.api    import    env\n%s' % action_dict['command']), context=env_vars)
            install_environment.handle_command(tool_dependency=tool_dependency, cmd=cmd, return_output=False, job_name=package_name)
        return (tool_dependency, None, None)
