最大目录深度

#!/bin/sh
count=0
while true
do
    mkdir deep-well
    if [ $? -ne 0 ];
    then
      echo "max dir deepth :$count"
      break
    fi
    count=$((count+1))
    cd deep-well
done

hanyh@hanyh-sina:/boot$ sudo sh mkdeep.sh
cd: 13: can't cd to deep-well
mkdir: 无法创建目录 “deep-well”: 文件已经存在
max dir deepth :410

410的数字是在那个地方定义的？