问用C语言实现Linux

EN

int main(int argk, char *argv[], char *envp[])
{
    int             frkRtnVal;  
    char           *v[NV];  
    char           *sep = " \t\n";
    int             i;      

    while (1)
    {
        fgets(line, NL, stdin);
        fflush(stdin);

        if (feof(stdin))
        {
            fprintf(stderr, "EOF pid %d feof %d ferror %d\n", getpid(), feof(stdin), ferror(stdin));
            exit(0);
        }

        if (line[0] == '#' || line[0] == '\n' || line[0] == '\000')
        {
            continue;
        }

        v[0] = strtok(line, sep);
        for (i = 1; i < NV; i++)
        {
            v[i] = strtok(NULL, sep);
            if (v[i] == NULL)
            {
                break;
            }
        }

        frkRtnVal = fork();
        switch (frkRtnVal)
        {
            case -1:
            {
                break;
            }
            case 0: 
            {
                execvp(v[0], v);
            }
            default:            
            {
                wait(0);
                break;
            }
        }
    }
}