如果执行这个代码
env -i X='() { (a)=>\' bash -c 'echo date' ; cat echo

出现如下类似内容，就需要继续升级了
bash: X: line 1: syntax error near unexpected token `='
bash: X: line 1: `'
bash: error importing function definition for `X'
Sat Sep 27 09:34:37 CST 2014

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