The one version should be for windows, linux and mac. I dont have linux or a mac so I cant verify, but it should work on all of them.
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linux executable exported from unity will have ".x86" or ".x86_64".
Some additional info found here:
http://ludumdare.com/compo/2013/12/24/unity-export-for-linux/
But you don't have to do it because of me its fine if you dont have time for that :)