#include <fcntl.h>;
#include <unistd.h>;
#include <sys/types.h>;
#include <sys/stat.h>;
int open(const char *pathname,int flags);
int open(const char *pathname,int flags,mode_t mode);
int close(int fd);

#include <unistd.h>;
ssize_t read(int fd, void *buffer,size_t count);
ssize_t write(int fd, const void *buffer,size_t count);if((from_fd=open(argv[1],O_RDONLY))==-1)
{
fprintf(stderr,"Open %s Error：%s\n",argv[1],strerror(errno));
exit(1);
}
/* 创建目的文件 */
if((to_fd=open(argv[2],O_WRONLY|O_CREAT,S_IRUSR|S_IWUSR))==-1)
{
fprintf(stderr,"Open %s Error：%s\n",argv[2],strerror(errno));
exit(1);
}