#include 
     
      #include 
      
       #include 
       
        #include 
        
         int main(int argc,char *argv[]){    if(argc<2)    {        printf("please print one param !\n");        return 0;    }    char buf[1024]={
   0};    char tmp[1024]={
   0};    sprintf(tmp,"df %s | sed -n '3p'|awk '{print $3}'",argv[1]);    FILE * file=popen(tmp,"r");    int count=0;    if(file!=NULL)    {        if(fgets(buf,1024,file)!=NULL)        {            long long freesize= strtoll(buf,NULL,10);            printf("size=%lld\n",freesize);        }    }    return 0;}