Find your OS X version using the command line —10 August 2014
Using the command line is always faster than going through graphical menus and windows with mouse clicks.
To find my OS X version using graphical tools, I have to move the mouse to the top left corner to the apple menu, which is not an ergonomic movement with a touchpad. Then click on the apple, select About This Mac, and click.
So much easier using the command line, especially when my hand is already on the keyboard:
$ sw_vers ProductName: Mac OS X ProductVersion: 10.9.4 BuildVersion: 13E28
To get even more details:
$ system_profiler SPSoftwareDataType Software: System Software Overview: System Version: OS X 10.9.4 (13E28) Kernel Version: Darwin 13.3.0 Boot Volume: Macintosh HD Boot Mode: Normal Computer Name: kronos User Name: Janos Gyerik (janos) Secure Virtual Memory: Enabled Time since boot: 25 days 14:19