You can find the boot device or boot path in Linux using any one of the following command:
- fdisk command – manipulate disk partition table
- sfdisk command – partition table manipulator for Linux.
- lsblk command – list block devices.
Open the terminal app or login to the remote server using ssh command. You must be root user and then type the following commands:
How to use lsblk to display boot partition
Simply type the following command:
$ lsblk
OR
$ lsblk -l
OR
$ lsblk /dev/sda
Sample outputs:
Fig.01: Linux lsblk command show boot device name
|-sda1 8:1 1 243M 0 part /boot
How to use fdisk command to display boot partition
Type the following command:
# fdisk -l
# fdisk -l /dev/sda
Sample outputs:
Fig.02: Linux fdisk command show boot device name
How to use sfdisk command to display boot partition
Type the following command:
# sfdisk -l
# sfdisk -l /dev/sda
Sample outputs:
Fig.03: Linux use sfdisk command show boot device name
A note about multiple devices (HDD/RAID)
If you’ve multiple hard drives or Linux software raid, it is going to be hard to find out this information. Consider the following:
# fdisk -l | grep '^Disk /dev'
Sample outputs:
Disk /dev/sdd: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors Disk /dev/sdc: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors Disk /dev/sda: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors Disk /dev/sdb: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors Disk /dev/sde: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors Disk /dev/md2: 1.5 TiB, 1610636328960 bytes, 3145774080 sectors Disk /dev/md1: 1.5 GiB, 1602748416 bytes, 3130368 sectors Disk /dev/md0: 120 GiB, 128877330432 bytes, 251713536 sectors Disk /dev/md3: 600 GiB, 644257677312 bytes, 1258315776 sectors Disk /dev/sdf: 492 MiB, 515899392 bytes, 1007616 sectors Disk /dev/mapper/securebackup: 600 GiB, 644256104448 bytes, 1258312704 sectors Disk /dev/mapper/cryptvg-mybackup: 600 GiB, 644253483008 bytes, 1258307584 sectors
I’ve multiple disk installed and Linux software RAID devices too. Here is a quick way to find out boot path or partition:
fdisk -l | grep '^/dev/[a-z]*[0-9]' | awk '$2 == "*"' ## OR ## fdisk -l | grep '^/dev/[a-z]*[0-9]' | awk '$2 == "*" { print $0}'
Sample outputs:
/dev/sdf1 * 62 1006879 1006818 491.6M 83 Linux
/dev/sdf1 is my boot path and to verify the same:
# fdisk -l /dev/sdf
Sample outputs:
Disk /dev/sdf: 492 MiB, 515899392 bytes, 1007616 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0x000e31b0 Device Boot Start End Sectors Size Id Type /dev/sdf1 * 62 1006879 1006818 491.6M 83 Linux
Disks GUI tool
There is an easy way to find all this information using the Disks GUI tool. It is a GNOME utility for dealing with storage devices. One can view, modify and configure disks and media using this simple tool. Start Disks from the Application menu or by pressing the Super key and typing Disks.
Summing up
With NVME SSD you need to look into /dev/nvme* device files. In my experience, the lsblk command gives out the most accurate information if you have a separate /boot partition. Otherwise, it would be best if you used the fdisk and friends. For instance:
lsblk | grep boot
Here is what I see:
│ └─md0 9:0 0 3.7G 0 raid1 /boot ├─nvme0n1p1 259:5 0 953M 0 part /boot/efi │ └─md0 9:0 0 3.7G 0 raid1 /boot
We can dig about the /dev/md0 by running the following cat command:
cat /proc/mdstat
So my boot device /dev/md0 is made of /dev/nvme0n1p2 and /dev/nvme1n1p2 partitions:
Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] md1 : active raid1 nvme0n1p3[0] nvme1n1p3[1] 995188736 blocks super 1.2 [2/2] [UU] bitmap: 5/8 pages [20KB], 65536KB chunk md0 : active raid1 nvme0n1p2[0] nvme1n1p2[1] 3903488 blocks super 1.2 [2/2] [UU] unused devices: <none>
We can see partition schema for each NVME SSD:
sudo fdisk -l /dev/nvme0n1
sudo fdisk -l /dev/nvme1n1
And my /dev/md0 is mounted at /boot/:
df /dev/md0
ls -l /boot/
The ls command finally indicated that /dev/md0 (Linux software RAID) is my boot device, and all Linux kernel files, EFI, and other boot files are located at /boot/ directory:
🐧 6 comments so far... add one ↓
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my test on debian, that lsblk -l doesn’t show any boot information, there is no mount point at /boot
You don’t provide how you ran the command, but I think you ran it as your regular user account; use sudo.
nyu@ What about fdisk command?
If you don’t have a “/boot” mount point, then you haven’t set up a separate boot partition. You will have booted directly off the root file system, “/”, then.
you can use “fdisk -l | awk ‘/^\/dev\/[a-z]*[0-9]/ && $2 ~ /\*/'” but from what I know, Linux can boots with boot flags on boot partition.
In my system the command
sudo fdisk -lproduces the output
It falsely reports /dev/sda1 as boot; it is an external not bootable hard disk (formatted as ext4).