Get OS Version From Scripts

It is sometimes useful to have a script check the OS version, for example the way to get the user’s full name was previously done using niutil but Apple removed that command in Leopard (it can now be done using dscl).

One BSD command to read OS properties is sysctl but prior to Leopard it didn’t offer kern.osrelease making it a bit awkward, as you had to keep track of how kern.osversion maps to a more humane number.

Lo and behold! Today I stumbled over sw_vers (x-man-page links fail when there is an underscore in the URL, so type man sw_vers in Terminal, rdar://7111174).

The manual page has no history, but the date is 2003 and an example in the manual page has 10.2.4 as output, so it goes way back.