自主实现简单的shell

#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<sys/wait.h>

char *argv[8];
int argc = 0;
void do_shell()
{
     pid_t pid;
     if((pid == fork()) == -1){
        peeror("fork");
        exit(EXIT_FAILURE);
     }
     if(pid == 0){
        execvp(argv[0],argv);
        perror("execvp");
     }else{
        int st;
        pid_t ret = wait(&st);
        if(ret == -1){
            perror("wait error");
            exit(-1);
        }
         }
}
void do_par(char *buf)
{
    int start = 0;
    int i = 0;
    argc = 0;
    while(buf[i]){
        if(!isspace(buf[i]) && start == 0){
            argv[argc++] = buf+i;
            start = 1;
         }
        else if(isspace(buf[i]) && start == 1){
            start = 0;
            buf[i] = '\0';
        }
        i++;
    }
    argv[argc++] = NULL;
}

int main()
{
    char buf[1024];
    while(1){
        printf("myshell->");
        scanf("%[^\n]%*c",buf);
        do_par(buf);
        do_shell();
       }
}