extern command_ret_t do_env_print(cmd_tbl_t *, int, int, char * const []);
extern command_ret_t do_env_default(cmd_tbl_t *, int, int, char * const []);
extern command_ret_t do_env_set(cmd_tbl_t *, int, int, char * const []);
extern command_ret_t do_env_print(cmd_tbl_t *, int, int, char * const []);
extern command_ret_t do_env_default(cmd_tbl_t *, int, int, char * const []);
extern command_ret_t do_env_set(cmd_tbl_t *, int, int, char * const []);