linux 文件操作 --copy_file

代码：

ngnsvr9 [** NONE **]/home/xionghailong/example $ cat copy_file.c

#include <unistd.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <stdlib.h>

#include <stdio.h>

#define BUFFER_SIZE 1024

#define SRC_FILE_NAME "src_file"

#define DEST_FILE_NAME "dest_file"

#define OFFSET 10240

int main()

{

int src_file, dest_file;

unsigned char buff[BUFFER_SIZE];

int real_read_len;

src_file = open(SRC_FILE_NAME, O_RDONLY);

dest_file = open(DEST_FILE_NAME, O_WRONLY|O_CREAT, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);

if (src_file < 0 || dest_file < 0)

{

printf("Open file error\n");

exit(1);

}

lseek(src_file, -OFFSET, SEEK_END);

while ((real_read_len = read(src_file, buff, sizeof(buff))) > 0)

{

write(dest_file, buff, real_read_len);

}

close(dest_file);

close(src_file);

return 0;

}

源文件：

ngnsvr9 [** NONE **]/home/xionghailong/example $ cat src_file

123456123456123456123456123456123456123456123456123456123456123456123456

编译运行结果：

ngnsvr9 [** NONE **]/home/xionghailong/example $ gcc copy_file.c -o copy_file

ngnsvr9 [** NONE **]/home/xionghailong/example $ ./copy_file

ngnsvr9 [** NONE **]/home/xionghailong/example $ cat dest_file

123456123456123456123456123456123456123456123456123456123456123456123456