#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>  //errno -l

//show with binary file.
int main(int argc, char *argv[]){
    if(argc < 2){
        fprintf(stderr, "Usage %s filename\n", argv[0]);
        return 1;
    }
    //change to argv
    //Try empty file
    //File that does not exist
    int fd = open(argv[1], O_RDONLY);
    printf("%d\n", fd);
    if (fd < 0) {
        //fprintf(stderr, "Could not open file (code %d)\n", errno);
        perror("Open");
        return 1;
    }
    char c;
    //Read more than 1 byte?
    while (read(fd, &c, 1) > 0) {
        printf("%c", c);
    }

    
    close(fd);
    return 0;
}