ReadWrite files to SD card


My goal is to write files to my SD card and after initializing my SD card, I tried to add another code to my teensy board 4.1 for example "ReadWrite" from the Library examples and it replaces the previous code. Anyone know why?
If I understand you correctly you are trying to upload two separate sketches into the T4.1 to be used together? If that is the case then it's not going to work. The second sketch will overwrite the first sketch. Every time you upload a sketch program memory is erased before the sketch is uploaded. In other words you can only have one sketch at a time in the T4.1 program memory. The best you can do is combine the sketches before you compile and then upload them to the Teensy. Hopefully this answers your question :D