linux实现CP指令

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
 
int main(int argc, char **argv)
{
    int fdSrc;
    int fdDes;
 
    char *readBuf=NULL;
 
    if(argc != 3){
        printf("pararm error\n");
        exit(-1);
    }
    
    fdSrc = open(argv[1],O_RDWR);
    int size = lseek(fdSrc,0,SEEK_END);
    lseek(fdSrc,0,SEEK_SET);
 
    readBuf=(char *)malloc(sizeof(char)*size + 8);
 
    int n_read = read(fdSrc, readBuf, size);
    
    //O_TRUNC 属性去打开文件时，如果这个文件中本来是有内容的，而且为只读或只写成功打开，则将其长度截短为0。
    fdDes = open(argv[2],O_RDWR|O_CREAT|O_TRUNC,0600);
       
    //strlen（）计算字符串长度
    int n_write = write(fdDes,readBuf,strlen(readBuf));
 
    close(fdSrc);
    close(fdDes);
 
    return 0;
}