#include <stdio.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <unistd.h>

#include <string.h>

#include <errno.h>

#define BUF_SIZE 1024

void cp(char *filename1, char *filename2)

{

        int fd1 = open(filename1, O_RDONLY);

        if (fd1 == -1) {

                printf("fail to open %s:%s\n", filename1, strerror(errno));

                return;

        }

        int fd2 = open(filename2, O_WRONLY | O_APPEND | O_CREAT, 0664);

        char szBuf[BUF_SIZE];

        int bytes;

        while(1) {

                memset(szBuf, 0, BUF_SIZE);

                bytes = read(fd1, szBuf, BUF_SIZE);

                if (bytes == 0) {

                        break;

                }

                write(fd2, szBuf, bytes);

        }

}

int main(int argc, char **argv)

{

        if (argc != 3 || !strcmp(argv[1], "--help")) {

                printf("Usage:%s [Src] [Dest]\n", argv[0]);

                printf("\tSrc:Source file\n");

                printf("\tDest:Destin file\n");

                return 0;

        }

        cp(argv[1], argv[2]);

        return 0;

}