Fix `open` failure in mac tmux

通常在mac的命令行下，open能够用来打开某个文件或者程序，就像在GUI下双击同样，很方便。 可是最近发现若是用了tmux，open命令常常会报错：bash The window server could not be contacted. open must be run with a user logged in at the console, either as that user or

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