/* MAIN PROCEDURE SECTION */
int main(int argc, char **argv)
{
   int pid = 0; //process ID
   int count = 1;
   char input[SHELL_BUFFER_SIZE];
   char iForm[15];
   sprintf(iForm,"%%%ds",SHELL_BUFFER_SIZE);
   while(1){
      printf("Shell(pid=%%%d)%%%d} ",pid,count);

      scanf(iForm, input);
      if(strcmp(input, "") != 0)
         count++;

      char *pt = NULL;
      char temp[strlen(input)+1];
      strcpy(temp,input);
      pt = strtok(temp, " ");
      //tokArr is an array of char*, each a token
      char *tokArr[strlen(input)];
      int i = 0;
      while(pt != NULL){
printf("%s\n", pt);
         tokArr[i] = pt;
         pt = strtok(NULL, " ");
         i++;
      }


      //cd
      if(strcmp(tokArr[0],"cd") == 0){
         chdir(tokArr[1]);
      }

      //termination
      else if(strcmp(tokArr[0],"exit") == 0){
         exit(0);
      }

      else{
         pid = fork();
         if(pid < 0){
            perror("Fork Failed");
            return -1;
         }
         else if(pid == 0){
            execvp(tokArr[0], tokArr+1);
         }
         else{
            wait(NULL);
         }
      }
   }
} /* end main() */

fgets(input,SHELL_BUFFER_SIZE,stdin);

pt = strtok(temp, ",");
. 
.
.
pt = strtok(NULL, ",");

int hsize = 20;
   char **hist = malloc(hsize * sizeof(char*));
   int j = 0;

   while(1){
      printf("Shell(pid=%%%d)%%%d} ",pid,count);

      fgets(input, SHELL_BUFFER_SIZE, stdin);
      if(strcmp(input, "") != 0)
         count++;

      char *pt = NULL;
      char temp[strlen(input)];
      strncpy(temp,input,strlen(input)-1);
      temp[strlen(input)-1] = '\0';

      if(j < hsize){
         hist[j] = malloc((strlen(temp)+1) * sizeof(char));
         strcpy(hist[j],temp);
         j++;
      }
      else{//double size of hist arr
         hsize*=2;
         void *error = realloc(hist, hsize);
         if(!error){
            printf("ERROR: realloc() fail.");
            exit(1);
         }
         hist[j] = malloc((strlen(temp)+1) * sizeof(char));
         strcpy(hist[j],temp);
         j++;
      }

char input[SHELL_BUFFER_SIZE+2];
.
.
.
fgets(input, SHELL_BUFFER_SIZE+2, stdin);
if(strlen(input)>0 && input[strlen(input)-1]=='\n')
    input[strlen(input)-1]='\0';
if (strlen(input)>SHELL_BUFFER_SIZE)
    // ERROR... To many characters read.