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how to write file to esp32 t8 sd card sdcard

https://github.com/nhatuan84/esp32-micro-sdcard

https://forum.arduino.cc/index.php?topic=594910.0

#include <SPI.h>
#include <mySD.h>
 
File root;
const int chipSelect = 13;
 
void setup()
{
  Serial.begin(115200);
  Serial.print("Initializing SD card...");
  pinMode(SS, OUTPUT);
 
 
  //SDClass::begin(uint8_t csPin, int8_t mosi, int8_t miso, int8_t sck)
  if (!SD.begin(13, 15, 2, 14)) {
    Serial.println("initialization failed!");
    return;
  }
 
  Serial.println("initialization done.");
 
  root = SD.open("/");
 
  printDirectory(root, 0);
 
  Serial.println("done!");
}
 
void loop()
{
  // nothing happens after setup finishes.
}
 
void printDirectory(File dir, int numTabs) {
  // Begin at the start of the directory
  dir.rewindDirectory();
 
  while(true) {
     File entry =  dir.openNextFile();
     if (! entry) {
       // no more files
       //Serial.println("**nomorefiles**");
       break;
     }
     for (uint8_t i=0; i<numTabs; i++) {
       Serial.print('\t');   // we'll have a nice indentation
     }
     // Print the 8.3 name
     Serial.print(entry.name());
     // Recurse for directories, otherwise print the file size
     if (entry.isDirectory()) {
       Serial.println("/");
       printDirectory(entry, numTabs+1);
     } else {
       // files have sizes, directories do not
       Serial.print("\t\t");
       Serial.println(entry.size(), DEC);
     }
     entry.close();
   }
}

to append

  auto myFile = SD.open("aaa.txt", O_APPEND | O_WRITE | O_CREAT);