BACK IN MY DAY:
I seem to remember once having precise-enough timing such that I booted true single-user mode successfully. This of course is not an option if you can’t boot the mac at all, but if you have and can boot to the Recovery Partition, the basic GUI is loaded but the System Drive is mounted read-only. This means running Disk Utility to repair the partition will not take up the remainder of time before your hardware is End-of-Lifed and command line fsck will work (although you may have to type the full path to it):
# /sbin/fsck -fy
# /sbin/mount -uw /
if you want to remount the System Drive as writable before you boot back into your whole-nine-yards OS X (e.g. to delete an gargantuan file someone may have created when you taught them about the magic of dd but didn’t consider the implications of
dd if=/dev/urandom of=/Users/stooey/teensy-file bs=512
without impressing the importance of the
(Pshaw! Of course you mentioned it! I always think of everything!)
I have been an Unix Admin for so long seeing a blank grey screen with the Apple logo may reinforce our voluntary brainwashing/zealotry, I prefer to see what’s happening in “real-time.” This can be of utmost importance when your machine is an OS X Server or just OS X who happens to be running server(s) ( must be connected to the network, but you want to at least know who’s doing what before you gave them your blessing or you’re acting outside the maintenance window and you hope nobody notices or tries to access any given facility you don’t want them to. They will, and they absolutely will.
THE SOLUTION (friggin’ finally!):
I changed the nvram so that whatever undermining force what activates my A.D.D. upon reboot (or I don’t want to appear to be a rube when educating and miss a crucial timeout expiry or App Store has been updating, and I’m busy SMSing, I have my system always boot verbose:
sudo nvram boot-args="-v"
but doing this to boot single-user (also implies verbose) is also possible:
sudo nvram boot-args="-s"
Once you've booted into it, you will want to change it to normal verbose boot or remove the argument in nvram (formerly PRAM for old souls [pre-Intel]) or it will always boot single-user mode which would make me a little despondent after very few reboots.
sudo nvram -d boot-args
HOPE THIS HELPS!