1 删除文件目录链接

解除链接unlink
• man 2 unlink
• 解除链接函数
• int unlink(const char pathname);
– 参数pathname：链接文件的路径
– 返回值：成功返回0，错误返回-1
– unlink指向软链接，删除软链接；指向最后一个硬链接，相当于删除文件

2文件的拷贝

拷贝文件
• Linux 下并没有专门的拷贝函数和接口，需要通过open，read，
wite 等文件操作函数实现

3移动文件命令为mv，函数为rename

• man 2 rename
• int rename(const char oldpath, const char newpath)
– 参数oldpath：旧的文件路径
– 参数newpath：新的文件路径
– 返回值：成功返回0，错误返回-1

4测试代码

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <dirent.h>
#include <stdio.h>

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

int main(int argv,char*argc[])
{
    
    int fdold,fdnew,len,ret;
    char rbuf[1024];
    
    //=====================================================
    //unlink
    printf("first file is unlink file or content  yyy\n");
    if(argv<2)
    {
       printf("no unlink file err \n");
       exit(1);
       
        
    }
    ret=unlink(argc[1]);
    if(0==ret)
    {
      printf("no unlink file %s success \n",argc[1]); 
    }else
    {
        
    printf(" unlink file %s fail %d \n",argc[1],ret);
     exit(1);
       
    }
    //==============================================================
    
    
    //===============================================================
    //file move
    printf("second file is need move file or content\n");
    if(argv<3)
    {
       printf("no move file err \n");
       exit(1);

    }
    
    if((fdold=open(argc[2],O_RDWR))<0)
    {
      printf("open old file %s err \n",argc[2]); 
       
    }
    
    
    if((fdnew=open(argc[3],O_RDWR|O_CREAT,0777))<0)
    {
      printf("open new file %s err \n",argc[3]); 
      
    }
    
    while(1)
    {
        len=read(fdold,rbuf,1024);
        if(len)
        write(fdnew,rbuf,len);
    else
        break;
    }
    
    
    close(fdold);
    close(fdnew);
    //=========================================================================
    
    
    
    //========================================================================
    //chgname
        printf("third file is ch name file or content\n");
    if(argv<4)
    {
       printf("no chgnaem file err \n");
       exit(1);

    }
    if(rename(argc[4], argc[5])<0)
    {
      printf("no chg name file err \n");
       exit(1);
        
    }
    printf("no chg name file success \n");
    
    
    //======================================================================
    return 0;
}