printf("loops %u / %u%c[K ", loops + 1, opts->loops, 27); printf("%cM", 27);

serialcheck.c中的一段代码一直弄不明白：

do {
        status = stress_test_uart_once(opts, fd, data, data_len);
        memset(opts->cmp_buff, 0, data_len);
        printf("loops %u / %u%c[K
", loops + 1, opts->loops, 27);
        if (!status)
            printf("%cM", 27);
    } while (++loops < opts->loops && !status);

查ansi

https://godoc.org/github.com/pborman/ansi#pkg-constants

EL     = Name("33[K")   // Erase in Line

RI     = Name("33M")    // Reverse Line Feed
33[K   清除从光标到行尾的内容 

Reverse Line Feed

line feed是打印机进一行纸,reverse line feed 是打印机退一行纸

/*RI-move up 1 line*/