簡單模仿命令列bash功能，模仿命令列bash

簡單模仿命令列bash功能，模仿命令列bash

       用LINUX有一段時間了，一致在bash底下輸入命令但是從來都很疑惑這個bash是如何知道我要輸入的什麼命令，於是用自己所學知識暫時模仿一些bash功能，後續繼續完善功能。

  第一次的版本：

/**********************************************************************   * Copyright (c)2015,WK Studios * Filename:   main.c * Compiler: GCC,VS,VC6.0  win32   * Author:WK   * Time: 2015 29 4 ************************************************************************/ #include<stdio.h> #include<stdlib.h>#include<string.h> int main() { char cmd[128]={0}; while(1) { printf("input command:");scanf("%s", cmd); if(0==strcmp(cmd,"help")) { printf("This is help command\n"); } else if(0==(strcmp(cmd,"quit")&&strcmp(cmd,"q"))) { exit(0); } else { printf("command not found\n"); } }}

第二次版本：

/**********************************************************************   * Copyright (c)2015,WK Studios * Filename:   bash.h * Compiler: GCC,VS,VC6.0  win32   * Author:WK   * Time: 2015 29 4 ************************************************************************/ #include<stdio.h>#include<stdlib.h>#include<string.h>#ifndef _BASH_H#define _BASH_H#define CMD_MAX_LEN 128#define DESC_LEN  1024#define CMD_NUM   10int help();int quit();int show(); typedef struct DataNode{    char *cmd;    char *desc;    int (*handler)();//函數指標    struct DataNode *next;}tDataNode;//  t表示typedef定義static tDataNode head[]=//鏈表數組{    {"help","This is help cmd",help,&head[1]},    {"version","Menu program v1.0",NULL,&head[2]},    {"quit","This is quit cmd",quit,NULL}//可以在數組中增加命令，這裡只有幾個命令};tDataNode* find(tDataNode* head,char *cmd); #endif

/**********************************************************************   * Copyright (c)2015,WK Studios * Filename:   bash.c * Compiler: GCC,VS,VC6.0  win32   * Author:WK   * Time: 2015 29 4 ************************************************************************/ #include"bash.h"tDataNode*  find (tDataNode *head,char *cmd){if(head==NULL|| cmd==NULL){return NULL;    }tDataNode *p=head;while(p!=NULL){if(strcmp(p->cmd,cmd)==0){return p;}p=p->next;}return NULL;}int show(tDataNode *head){tDataNode *p=head;printf("Menu List:\n");while(p!=NULL){printf("%s - %s\n",p->cmd,p->desc);p=p->next;}return 1;}int help()//列印所有命令{    show(head);return 1;}int quit(){exit(0);}

/**********************************************************************   * Copyright (c)2015,WK Studios * Filename:   main.c * Compiler: GCC,VS,VC6.0  win32   * Author:WK   * Time: 2015 29 4 ************************************************************************/ #include"bash,h"int main(){while(1){    char cmd[CMD_MAX_LEN];printf("Input a command number>");scanf("%s",cmd);tDataNode *p=find(head,cmd);if(p==NULL){printf("command not found!\n");continue;}printf("%s - %s\n",p->cmd,p->desc);if(p->handler != NULL)//有點多態的意思調用同一個handler效果不同{            p->handler();//function point}}return 0;}