在山狮上结合grep -m和-A

Question

在Mountain Lion上，grep似乎产生了奇怪的结果。下面的陈述返回3而不是预期的 3
4

set xxx to "
2
3
4
5
"

set variableName to do shell script "echo " & quoted form of xxx & " | grep -m1 -A1 3"