Command line - change start up disk

Zoboomafoo

Registered
I need to change the start up disk to be a different disk instead of my OS X disk.

OS X cannot see the disk I want it to use.

I cannot change the start up disk back in OS X's settings.

How do I use the command line in OS X to fix it?
  • 2009 Macbook Pro
  • OS X El Capitan
 

DeltaMac

Tech
If the boot disk that you want to use is too new, such as an APFS volume -- and you are booting to an older system that can't see that APFS volume, then nothing in your terminal will see it either.
What system is on the different disk?
How do you choose to boot to that different disk now?
 

Zoboomafoo

Registered
Ubuntu 16.04

It used to boot straight to Ubuntu.
I used the alt/option menu on startup to get to OS X.
Ubuntu didn't show up on that menu.

Now it boots straight to OS X.
A Mac tech added a user in OS X right before it stopped working.





How it worked before

I installed Ubuntu and OS X like this:
  • Partition drive
  • Install OS X
  • Install Ubuntu
Doing this lets the computer boot straight to Ubuntu.

OS X is then accessible through the alt/option menu.
 

DeltaMac

Tech
Ah, OK...
Ubuntu (and most flavors of linux) use their own booters, which are installed at the time of the initial Ubuntu install
The "tech" that you said added a user, may have done more than that, perhaps doing what I call a "health install", which is a simple reload of macOS. That would help explain why your Ubuntu boot option disappeared, as a macOS reinstall may disturb a third-party boot setup.
There should be a way to fix this, but you may need to look at a site that has tech support for Ubuntu. You would look for how to reload the boot setup for your Ubuntu install. You might end up reinstalling Ubuntu.
 

Zoboomafoo

Registered
Surprisingly, it was from something as low level as creating a new user in the Settings panel of OS X. I was sitting with him.

Linux boards say they can't fix it, so I have been looking for places that know about OS X's command line.

Do you know any other places where people dig deep into OS X?
 

Satcomer

In Geostationary Orbit
Surprisingly, it was from something as low level as creating a new user in the Settings panel of OS X. I was sitting with him.

Linux boards say they can't fix it, so I have been looking for places that know about OS X's command line.

Do you know any other places where people dig deep into OS X?
Just go into Terminal and manual Network Setup:

 
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