Linux代码实现“cat 文件名”

#include "stdio.h"
#include "sys/fcntl.h"
#include "stdlib.h"
int main(int argc,char* argv[]){
        int fd;
        char buf[10];
        int num;
        if(argc!=2){
                printf("filename miss!");
                exit(1);
        }
        fd=open(argv[1],O_RDONLY);
        if(fd==-1){
                printf("error");
                exit(1);
        }
        while((num=read(fd,buf,10))!=0)
        {
                write(1,buf,num);
        }
        close(fd);
return 0;
}