http://www.wechall.net/challenge/can_you_readme/index.php
这道题试了下没发现什么漏洞，所以只好老老实实地去做识别了
搜了下有tesseract这个软件可以做ocr，于是用下面的脚本：
#!/bin/bash
wget -O ocr.png --no-cookies --header "Cookie:WC=7390992-11403-6nnwUyENAALTe4VK"\
http://www.wechall.net/challenge/can_you_readme/gimme.php
tesseract ocr.png ocr -psm 7
SOLUTION=`head -1 ocr.txt`
curl -b "WC=7390992-11403-6nnwUyENAALTe4VK" -G -d "solution=$SOLUTION" -d "cmd=Answer"\
http://www.wechall.net/challenge/can_you_readme/index.php