Sure you can. Enter BIOS/UEFI, go to "Boot" tab and set boot priority #1 to be the storage device you wanna boot from. If grub is installed on another device, this will skip it completely.I can do "df" and "reboot -f" but
can I directly boot to /dev/sdx ?
On multiboot system, thus bypassing "grub"?
Likes
"boot /dev/sda2 " ?
Sure you can. Enter BIOS/UEFI, go to "Boot" tab and set boot priority #1 to be the storage device you wanna boot from. If grub is installed on another device, this will skip it completely.
On the same device - doubtful. I've never had multiple OS on the same device, that's a very bad idea, so I really don't know.I need to try this, but will it work if I have a multiple OS on device?
No, it won't. You can't boot directly to a partition, you can make your pc boot to a different disk, not to a specific partition within the same disk; 1 disk = 1 bootloader. You can change the boot order so instead of Ubuntu it boots to something else, you just need to edit /boot/grub/grub.cfgI need to try this, but will it work if I have a multiple OS on device?
sudo nano /boot/grub/grub.cfg
I've never had multiple OS on the same device, that's a very bad idea,...
On the same device - doubtful. I've never had multiple OS on the same device, that's a very bad idea, so I really don't know.
The only time it's a bad idea is to run multiple OSes on one disk is when you are trying to install Windows and Linux on the same disk since Windows doesn't read ext4 or xfs and GNU/Linux doesn't read ntfs during boot.Nonsense.
I have 12 on my 256 GB SSD, 32 on my SATA 2 TB internal HDD, and 24 on my Western Digital My Book 4 TB external powered drive, total 68 on the one system.
Put 2 or more different editions of Windows 7, of Windows 8 or of Windows 10 on the same storage device and then you'll see the problems I was talking about. Even 1 edition of Windows 7 and 1 of Windows 10 are enough to cause the trouble bc the same drivers will start fighting each other for dominance.put 8 Linux on with it
I wouldn't agree. I keep Windows around for firmware updates and haven't had any issues due to that.that's a very bad idea
On multiboot system, thus bypassing "grub"?
Like I said here, you can configure your pc so it boots to a desired OS of your choice by default, if you have more than 1 installed in the same disk, you just need to edit /boot/grub/grub.cfgWow, my reaction - did some of you bother to read the post - and stay on the subject ?
The answer should be - no , there is no command to boot directly to OS .
And yes - it works better when you plug it in....
sudo nano /boot/grub/grub.cfg
You need a bootloader to boot the the system, even with Windows. With bios systems the BIOS looks at the MBR which launches the bootlader which than boots the kernel. With uefi systems UEFI looks at the efi boot loader which then launches the kernel, so technically with efi boot systems you don't need a bootloader such as Grub. This is AFAIK what systemd-boot does it launches the uefi bootloader, but most systems use Grub anyways. I haven't really used systemd-boot much so I may not be right on everything and I'm not great at explaining things but that's the basic idea of how booting works. So no you cannot boot directly to a specific partition using a command, but you can configure your bootloader to boot a specific OS by default as @Tolkem already explained.I can do "df" and "reboot -f" but
can I directly boot to /dev/sdx ?
On multiboot system, thus bypassing "grub"?
Likes
"boot /dev/sda2 " ?
P.S having an attitude when people take the time to respond to your post isn't going to help anyone.Wow, my reaction - did some of you bother to read the post - and stay on the subject ?
The answer should be - no , there is no command to boot directly to OS .
And yes - it works better when you plug it in....
You need a bootloader to boot the the system, even with Windows. With bios systems the BIOS looks at the MBR which launches the bootlader which than boots the kernel. With uefi systems UEFI looks at the efi boot loader which then launches the kernel, so technically with efi boot systems you don't need a bootloader such as Grub. This is AFAIK what systemd-boot does it launches the uefi bootloader, but most systems use Grub anyways. I haven't really used systemd-boot much so I may not be right on everything and I'm not great at explaining things but that's the basic idea of how booting works. So no you cannot boot directly to a specific partition using a command, but you can configure your bootloader to boot a specific OS by default as @Tolkem already explained.
P.S having an attitude when people take the time to respond to your post isn't going to help anyone.
You already had your answer in post #7.So I have an attitude when I point out that most of the replies are off topic rambling ?
( some people just cannot face reality and always blame the user , easy way out duh )
Secondly _ I posted to help myself and not to educate others - they are free to ask their own questions.
And how do off-topic opionins are going to help "anyone" anyway?
As for being off-topic, the topic as you presented it was a question about booting and multi-boot. Your original question was maybe 2-3 short sentences, if you would have taken the time to present it a bit more thoroughly than you might have gotten better answers and less answers that weren't helpful to you. People responded based on what they thought you meant or were looking, responding with information about what you could do with grub as in changing the boot order etc. How much effort you put into something is how much you will get out of something.No, it won't. You can't boot directly to a partition, you can make your pc boot to a different disk, not to a specific partition within the same disk; 1 disk = 1 bootloader.