This is the output of lsblk command on my Ubuntu machine:
$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
loop0 7:0 0 1.7G 1 loop /snap/0ad/592
…
sda 8:0 0 111.8G 0 disk
├─sda1 8:1 0 619M 0 part /boot/efi
├─sda2 8:2 0 954M 0 part [SWAP]
└─sda3 8:3 0 110.3G 0 part /home
sdb 8:16 0 931.5G 0 disk
└─sdb1 8:17 0 931.5G 0 part /
sr0 11:0 1 383.5M 0 rom
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
loop0 7:0 0 1.7G 1 loop /snap/0ad/592
…
sda 8:0 0 111.8G 0 disk
├─sda1 8:1 0 619M 0 part /boot/efi
├─sda2 8:2 0 954M 0 part [SWAP]
└─sda3 8:3 0 110.3G 0 part /home
sdb 8:16 0 931.5G 0 disk
└─sdb1 8:17 0 931.5G 0 part /
sr0 11:0 1 383.5M 0 rom
I wanted to get total size of disks sda and sdb together, but I wanted to use bash to do it.
First, I only get lines beginning with sda or sdb:
$ lsblk | grep -Pi ‘^sda|^sdb’
sda 8:0 0 111.8G 0 disk
sdb 8:16 0 931.5G 0 disk
sda 8:0 0 111.8G 0 disk
sdb 8:16 0 931.5G 0 disk
Then we isolate just the fourth column delimited by spaces (that is SIZE column).
$ lsblk | grep -Pi ‘^sda|^sdb’ | awk ‘{print $4}’
111.8G
931.5G
111.8G
931.5G
Next step would be to add 111.8G and 931.5G together. So we do that:
$ lsblk | grep -Pi ‘^sda|^sdb’ | awk ‘{print $4}’ | awk ‘{total+=$1} END {printf “%.1fGn”,total}’
1043.3G
1043.3G
Lastly, let’s convert the answer to terabytes (since the answer is in gigabytes):
logan@logan-mainPC:~$ lsblk | grep -Pi ‘^sda|^sdb’ | awk ‘{print $4}’ | awk ‘{total+=$1} END {printf “%.1fGn”,total}’ | awk ‘{terabyte=$1/1000; printf “%.1fTn”,terabyte}’
1.0T
1.0T
So we conclude that 1043.3G is about 1T in size. Now we know that we would need at least 1T of space to copy the contents of both sda and sdb to another hard disk. 🙂
