Safari unzips .zip and .gz files after downloading. How can I stop this behavior?
In the menu bar, go Safari -> Preferences. In the "General" tab, uncheck "Open 'safe' files after downloading". This will stop Safari from automatically unzipping the files.
Just hold the ⌥ alt button while clicking on the download links.
Tested on OS X Mavericks.
In Preferences, at the bottom of the General tab, uncheck the "Open "safe" files after downloading" check box.
Check out this article if you want to keep the "Safe Downloads" behavior but tweak it a little.