copy a file

copy.c

// Copy a file.
// Removed all error hanlders for simplicity.

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

#ifndef BUF_SIZE
#define BUF_SIZE 4096
#endif

// ssize_t read(int fd, void *buf, size_t count);
//
// int open(const char *pathname, int flags);
// int open(const char *pathname, int flags, mode_t mode);
// ssize_t write(int fd, const void *buf, size_t count);

int main(int argc, char const *argv[]) {
    int fd = open(argv[1], O_RDONLY);
    char buf[BUF_SIZE];
    int outfd = open(argv[2], O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
    ssize_t nread;
    while ((nread = read(fd, buf, BUF_SIZE)) > 0) {
        write(outfd, buf, nread);
    }
    return 0;
}