# Command line - change start up disk



## Zoboomafoo (Aug 20, 2019)

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


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## DeltaMac (Aug 20, 2019)

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?


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## Zoboomafoo (Aug 21, 2019)

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.


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## DeltaMac (Aug 21, 2019)

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.


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## Zoboomafoo (Aug 21, 2019)

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?


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## Satcomer (Aug 31, 2019)

Zoboomafoo said:


> 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:









						networksetup – Change Network Settings from the Command Line
					

UPDATE (8/12/08): I simplified the awk portion of the command. Mac OS X comes with a very convenient tool called networksetup that makes it relatively easy to view or change network settings from t…




					yourmacguy.wordpress.com


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