Applescript 从ssh keygen获取默认位置？

使用ssh keygen时，如果未指定默认目录，则显示默认目录：

Enter file in which to save the key (/Users/username/.ssh/id_rsa): 

我需要获取路径和文件名“/Users/monkeypunch/.ssh/id\u rsa”

这个怎么样：

to getDefaultKeyPath()
    try
        do shell script ("ssh-keygen")
    on error response
        set oldDelim to AppleScript's text item delimiters
        set AppleScript's text item delimiters to {"(", ")"}
        set defaultKeyPath to text item 2 of response
        set AppleScript's text item delimiters to oldDelim
    end try
    return defaultKeyPath
end getDefaultKeyPath

getDefaultKeyPath（）将返回

/Users/monkeypunch/.ssh/id\u rsa