OS X 10.11 shipped earlier this week, and I haven't come across any bad experience stories on the Internet (it sounds like a solid release of OS X), so it's upgrade weekend for me.
I install a lot of one-time-use libraries and executables via homebrew, OS X packages and try out a lot of applications that litter files everywhere, so with each major upgrade I prefer to start over fresh. I do this often and want to outline how some tricks that has made the process easier for me.
Keep things in order
First up, keep your personal documents, pictures, music, movies, etc in order and backed up or synced. I like to use Dropbox for documents and pictures, and iCloud for calendars, contacts and scratch notes. Pictures are also backed up with Arq to a local NAS where my movies and music are, too.
The less you have to plan to backup, the more at ease you will feel because you won't have this nagging feeling like you forgot something after you have formatted your system drive.
My development environment is reproducible too. I like to make sure the on-boarding process for a project is automated or at least the documentation is up to date. Most projects are provisioned with Ansible and Vagrant, and the projects that aren't tend to be easy to setup without a crazy number of dependencies.
Create a OS X 10.11 boot disk
You need an 8GB flash drive and the El Capitan installer.
Prep the flash drive in Disk Utility so that it's formatted as a Mac OS Extended (Journaled) volume with a GUID Partition Table.
The El Cpaitan installer includes a utility to create an install disk built in, so there is no need to get crazy with additional applications or trying to build one yourself. Just know, though, it will replace everything on that drive.
Run the following command in the terminal:
sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app --nointeraction
Note, the name of the flash drive,
/Volumes/Untitled, if you formatted your flash drive with a different name, change the command above before running or it will fail.
Turn off "Find My Mac" from the iCloud control panel, if you have it enabled, before rebooting, or you will not be able to format the disk for a clean install.
Reboot your Mac and hold down the
Option key when it's booting to select the boot drive. When the installer is booted, run Disk Utility first to format before installing OS X.
Automate system tweaks
There are a lot of little checkboxes and dropdown menus that I like to go through before using a system, like turning on secondary mouse click (right click) and disabling autocorrect.
These tweaks via the GUI do nothing more than write out preference files that system or other system apps read at launch and thus can be automated for the next time.
Check out this rather large, well documented list of OS X preferences and see if there are any that you know you always set when you boot a Mac for the first time. Copy and paste the ones you like to your own notepad or dotfiles repo.
My OS X init script on Github.
Try new things
Next year there will probably be another major update to OS X, so have fun trying out a new IDE that litters files all over your Mac or give Adobe Creative Suite a try and realize it's almost impossible to completely uninstall.
By having your personal files synced and backed up, your install media handy and your favorite system tweaks a copy and paste in to a terminal away, you probably won't worry about it. You'll know you can always wipe and re-install with ease if it gets way too crazy on your Mac.