为什么此串行/调制解调器代码弄乱了我的终端显示

我已经编写了一些代码，以基本上是使用Regex/dev/tty*在UNIX系统上找到任何调制解调器命令并检查响应消息是否包含字符"确定"。

代码确实找到了调制解调器，但不幸的是，它弄乱了终端显示屏。见下文。我注意到它也打印出AT命令 - 请参见下面的输出。为什么我的终端显示器更改了？我该如何解决？

运行程序后，如果输入命令并输入，例如LS，则未显示命令，但是当您按Enter时，您会看到输出。

这是代码：

#include <iostream>
#include <string>
#include <unordered_map>
#include <iomanip>
#include <memory>
#include <sstream>
#include <thread>
#include <iostream>
#include <filesystem>
#include <regex>
#include <unistd.h>  // close
#include <fcntl.h>   // open, O_RDWR, etc
#include <termios.h>
#include <string.h>
#include <sys/select.h>  // timeouts for read
#include <sys/timeb.h>   // measure time taken
int set_interface_attribs(int fd, int speed)
{
    struct termios tty;
    if (tcgetattr(fd, &tty) < 0) {
        // Error from tcgetattr - can use strerror(errno)
        return -1;
    }
    cfsetospeed(&tty, (speed_t)speed);
    cfsetispeed(&tty, (speed_t)speed);
    tty.c_cflag |= (CLOCAL | CREAD);    /* ignore modem controls */
    tty.c_cflag &= ~CSIZE;
    tty.c_cflag |= CS8;         /* 8-bit characters */
    tty.c_cflag &= ~PARENB;     /* no parity bit */
    tty.c_cflag &= ~CSTOPB;     /* only need 1 stop bit */
    tty.c_cflag &= ~CRTSCTS;    /* no hardware flowcontrol */
    /* setup for non-canonical mode */
    tty.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL | IXON);
    tty.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
    tty.c_oflag &= ~OPOST;
    /* fetch bytes as they become available */
    tty.c_cc[VMIN] = 1;
    tty.c_cc[VTIME] = 1;
    if (tcsetattr(fd, TCSANOW, &tty) != 0) {
      // Error from tcsetattr- use strerror(errno)
        return -1;
    }
    return 0;
}
long enumerate_ports(std::unordered_map <std::string, std::string>& ports) {
    // ls /dev | grep ^tty.*
    const std::regex my_filter( "^tty.*" );
    std::string path = "/dev/";
    for (const auto & entry : std::filesystem::directory_iterator(path)) {
     std::smatch sm;
     std::string tmp = entry.path().filename().string();
     // if we have a regex match attempt to open port and send AT command
     if (std::regex_match(tmp, sm, my_filter)) {
     std::string portname = entry.path().string();
         int fd = ::open(portname.c_str(), O_RDWR | O_NOCTTY);
         if (fd < 0) {
       // Error opening port
             continue;
         } else {
       // port was opened successfully
           // try to write AT command and do we get an OK response
           // baudrate 9600, 8 bits, no parity, 1 stop bit
           if(set_interface_attribs(fd, B9600) != 0) {
             ::close(fd);
         continue;
           }
           int wlen = ::write(fd, "ATrn", 4);
           if (wlen != 4) {
         // Error from write
               ::close(fd);
               continue;
           }
          // tcdrain() waits until all output written to the object referred 
          // to by fd has been transmitted.
           tcdrain(fd);
           fd_set set;
           struct timeval timeout;
           FD_ZERO(&set); /* clear the set */
           FD_SET(fd, &set); /* add our file descriptor to the set */
           timeout.tv_sec = 0;
           timeout.tv_usec = 100000; // 100 milliseconds
           // wait for data to be read or timeout
           int rv = select(fd + 1, &set, NULL, NULL, &timeout);
           if(rv > 0) {  // no timeout or error
               unsigned char buf[80];
               const int bytes_read = ::read(fd, buf, sizeof(buf) - 1);
               if (bytes_read > 0) {
                   buf[bytes_read] = 0;
                   unsigned char* p = buf;
                   // scan for "OK"
                   for (int i = 0; i < bytes_read; ++i) {
             if (*p == 'O' && i < bytes_read - 1 && *(p+1) == 'K') {
                       // we have a positive response from device so add to ports
                       ports[portname] = "";
                       break;
                     }
                     p++;
                   }
               }
        }
       ::close(fd);
         }
     }
   }
   return ports.size();
}

int main() {
    struct timeb start, end;
    int diff;
    ftime(&start);
    // get list of ports available on system
    std::unordered_map <std::string, std::string> ports;
    long result = enumerate_ports(ports);
    std::cout << "No. found modems: " << result << std::endl;
    for (const auto& item : ports) {
        std::cout << item.first << "->" << item.second << std::endl;
    }
    ftime(&end);
    diff = (int) (1000.0 * (end.time - start.time)
        + (end.millitm - start.millitm));
    printf("Operation took %u millisecondsn", diff);
}

和输出：

acomber@mail:~/Documents/projects/modem/serial/gdbplay$ ls
main.cpp  main.o  Makefile  serial
acomber@mail:~/Documents/projects/modem/serial/gdbplay$ make serial
g++ -Wall -Werror -ggdb3 -std=c++17 -pedantic  -c main.cpp
g++ -o serial -Wall -Werror -ggdb3 -std=c++17 -pedantic  main.o -L/usr/lib -lstdc++fs
acomber@mail:~/Documents/projects/modem/serial/gdbplay$ sudo ./serial
[sudo] password for acomber: 
AT
No. found modems: 1
                   /dev/ttyACM0->
                                 Operation took 8643 milliseconds
                                                                 acomber@mail:~/Documents/projects/modem/serial/gdbplay$