Bsrgvty

My goal is to get the disks greater than 100G from lsblk.

I have it working, but it's awkward. I'm pretty sure it can be shortened. Either by using something totally different than lsblk, or maybe I can filter human readable numbers directly with awk.

Here's what I put together:

lsblk | grep disk | awk 'print$1,$4' | grep G | sed 's/.$//' | awk 'if($2>100)print$1'

It outputs only the sdx and nvmexxx part of the disks larger than 100G. Exactly what I need.

I am happy with it, but am eager to learn more from you Gurus 😉

You can specify the form of output you want from lsblk:

% lsblk -nblo NAME,SIZE
mmcblk0 15931539456
mmcblk0p1 268435456
mmcblk0p2 15662038528

Options used:

-b, --bytes
 Print the SIZE column in bytes rather than in human-readable format.

-l, --list
 Use the list output format.

-n, --noheadings
 Do not print a header line.

-o, --output list
 Specify which output columns to print. Use --help to get a list of all supported
 columns.

Then the filtering is easier:

% lsblk -nblo NAME,SIZE | awk '$2 > 4*2^30 print $1' # greater than 4 GiB
mmcblk0
mmcblk0p2

In your case, that'd be 100*2^30 for 100GiB or 100e9/1e11 for 100GB.

You can also tell lsblk to output in JSON format and do the filtering with jq:

$ lsblk -Jb | jq -r '..|select(.size? >= 1e11).name'
sda
sda2

Or:

$ lsblk -Jb | jq -r '..|select(.type? == "disk" and .size? >= 1e11).name'
sda

To limit to entries of type disk.

(1e11 being 100 GB. Replace with 107374182400 (or 100*1024*1024*1024) for 100 GiB. Because of rounding, lsblk itself without -b reports 100G for sizes ranging from about 99.9278 to 100.0488 GiB (for some reason))

With lsblk -OJb, lsblk reports all available information which lets you do a more fined-grained selection or output more or more relevant information.

You could also get the information directly from /sys. With zsh:

$ printf '%sn' /sys/class/block/*(e'[(($(<$REPLY/size) * 512 >= 1e11))]':t)
sda
sda2

try

lsblk| awk '$4 ~ /G$/ && $4+0 > 100 print $1'

this will grep and filter at same time.

• 
  $4 ~ /G$/ get filed with size in G


• 
  $4+0 > 100 get size over 100G


• 
  print $1 print NAME

as a rule you should never need to use grep and awk in same pipe.

to get only disk (and no partition) : awk filtering

lsblk| awk '$4 ~ /G$/ && $4+0 > 100 && $6 == "disk" print $1'

where

• 
  $6 == "disk" select only column with disk

to get only disk (and no partition) : lsblk filtering

lsblk --nodeps| awk '$4 ~ /G$/ && $4+0 > 100 print $1'

where

• 
  --nodeps : -d, --nodeps don't print slaves or holders