获得命令方块

/give @p 137

PS：这个方法在1.8以上无法实现

先放一个命令方块,命令方块上放一个按钮

命令方块代码：

/summon MinecartCommandBlock ~-1 ~ ~ {Riding:{id:"MinecartCommandBlock",Riding:{id:"MinecartCommandBlock",Riding:{id:"MinecartCommandBlock",Command:"/setblock ~-1 ~1 ~ 0 0 destroy"},Command:"/setblock ~-1 ~ ~ 0 0 destroy"},Command:"/setblock ~-1 ~-2 ~ 152 0 replace"},Command:"/setblock ~-1 ~-1 ~ 157 0 replace"}

在命令方块的W方向 放一块红石,红石上方放一个激活铁轨

再右击按钮激活命令方块

激活后会出现命令矿车,推一下命令矿车试试

4个方向不同的代码(往哪个方向挖就用哪个方向的代码)：

W方向：

/summon MinecartCommandBlock ~-1 ~ ~ {Riding:{id:"MinecartCommandBlock",Riding:{id:"MinecartCommandBlock",Riding:{id:"MinecartCommandBlock",Command:"/setblock ~-1 ~1 ~ 0 0 destroy"},Command:"/setblock ~-1 ~ ~ 0 0 destroy"},Command:"/setblock ~-1 ~-2 ~ 152 0 replace"},Command:"/setblock ~-1 ~-1 ~ 157 0 replace"}

S方向：

/summon MinecartCommandBlock ~ ~ ~1 {Riding:{id:"MinecartCommandBlock",Riding:{id:"MinecartCommandBlock",Riding:{id:"MinecartCommandBlock",Command:"/setblock ~ ~1 ~1 0 0 destroy"},Command:"/setblock ~ ~ ~1 0 0 destroy"},Command:"/setblock ~ ~-2 ~1 152 0 replace"},Command:"/setblock ~ ~-1 ~1 157 0 replace"}

E方向：

/summon MinecartCommandBlock ~1 ~ ~ {Riding:{id:"MinecartCommandBlock",Riding:{id:"MinecartCommandBlock",Riding:{id:"MinecartCommandBlock",Command:"/setblock ~1 ~1 ~ 0 0 destroy"},Command:"/setblock ~1 ~ ~ 0 0 destroy"},Command:"/setblock ~1 ~-2 ~ 152 0 replace"},Command:"/setblock ~1 ~-1 ~ 157 0 replace"}

N方向：

/summon MinecartCommandBlock ~ ~ ~-1 {Riding:{id:"MinecartCommandBlock",Riding:{id:"MinecartCommandBlock",Riding:{id:"MinecartCommandBlock",Command:"/setblock ~ ~1 ~-1 0 0 destroy"},Command:"/setblock ~ ~ ~-1 0 0 destroy"},Command:"/setblock ~ ~-2 ~-1 152 0 replace"},Command:"/setblock ~ ~-1 ~-1 157 0 replace"}