Before the update
> bash --version
GNU bash, version 3.2.51(1)-release (x86_64-apple-darwin13)
Copyright (C) 2007 Free Software Foundation, Inc.
After the update
> bash --version
GNU bash, version 3.2.53(1)-release (x86_64-apple-darwin13)
Copyright (C) 2007 Free Software Foundation, Inc.
Get the update from the Apple Support site.
The install is simple, open the .DMG file and double-click the installer. No restart is needed.
-i