//    Intro to Systems Programming, the C Language, and Tools for Software Engineering
//    https://www.bilibili.com/video/BV1Mu411Q7Md
//    https://www.youtube.com/watch?v=Rhf6iOeahk8










#include <unistd.h>
#include <fcntl.h>

#define BUFFER_SIZE 80
char buffer[BUFFER_SIZE];


//int main()
//{
//    read(0, buffer, 5);
//    write(1, buffer, 3);
//}
//
//gcc cat.c
//    ./a.out
//
//input: 123456
//output: 123 //6: is not a command



//int main()
//{
//    ssize_t bytes_read;
//    bytes_read = read(0, buffer, 5);
//    write(1, buffer, bytes_read);
//}
//input: 1234567
//output: 12345 //7: command not found...



//int main()
//{
//    ssize_t bytes_read;
//    bytes_read = read(0, buffer, 80);
//    write(1, buffer, bytes_read);
//}
//input: 12345
//output: 12345



int main()
{
    ssize_t bytes_read;
    bytes_read = read(0, buffer, 80);
    write(1, buffer, bytes_read);
}



//    ...