UNIX 프로그래밍에서 chdir과 관련하여 질문 드립니다.

#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#define MAX_CMD_ARG 10
 
const char *prompt = "myshell> ";
char* cmdvector[MAX_CMD_ARG];
char  cmdline[BUFSIZ];
 
void fatal(char *str){
	perror(str);
	exit(1);
}
 
int makelist(char *s, const char *delimiters, char** list, int MAX_LIST){	
  int i = 0;
  int numtokens = 0;
  char *snew = NULL;
 
  if( (s==NULL) || (delimiters==NULL) ) return -1;
 
  snew = s + strspn(s, delimiters);	/* delimiters를 skip */
  if( (list[numtokens]=strtok(snew, delimiters)) == NULL )
    return numtokens;
 
  numtokens = 1;
 
  while(1){
     if( (list[numtokens]=strtok(NULL, delimiters)) == NULL)
	break;
     if(numtokens == (MAX_LIST-1)) return -1;
     numtokens++;
  }
  return numtokens;
}
 
int main(int argc, char**argv){
  int i=0;
  pid_t pid;
  while (1) {
 
  	fputs(prompt, stdout);
	fgets(cmdline, BUFSIZ, stdin);
	cmdline[ strlen(cmdline) -1] ='\0';
 
        i = makelist(cmdline, " \t", cmdvector, MAX_CMD_ARG);
 
        if(strcmp (cmdline, "exit") == 0)
        {
             exit(1);
        }
 
  	switch(pid=fork()){
	case 0:
               /* chdir("/bin") 이렇게 하는 거 아닌가요? */
                execvp(cmdvector[0], cmdvector);
		fatal("main()");
	case -1:
  		fatal("main()");
	default:
		wait(NULL);
	}
  }
  return 0;
}