#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <strings.h>
#include <string.h>

char* shellcmd(char* cmd, char* buff, int size)
{
  char temp[256];
  FILE* fp = NULL;
  int offset = 0;
  int len;
  
  fp = popen(cmd, "r");
  if(fp == NULL)
  {
    return NULL;
  }

  while(fgets(temp, sizeof(temp), fp) != NULL)
  {
    len = strlen(temp);
    if(offset + len < size)
    {
      strcpy(buff+offset, temp);
      offset += len;
    }
    else
    {
      buff[offset] = 0;
      break;
    }
  }
  
  if(fp != NULL)
  {
    pclose(fp);
  }

  return buff;
}

int main(void)
{
  char buff[1024];

  memset(buff, 0, sizeof(buff));
  printf("%s", shellcmd("ls", buff, sizeof(buff)));

  return 0;
}