Does my Ubuntu-based computer use EFI?

Intro and howto

So, I use Veeam Backup Agent for Linux for backing up my desktops and laptops.

This solution offer a recovery ISO you use to boot from in order to do a bare-metal restore.

The recovery ISO sometimes needs certain drivers to be available, and therefore you need to patch it.
When patching the recovery ISO, you need to know if the computer system is legacy BIOS och EFI.

A simple way to check if the computer is using EFI or not is to run the below command in a terminal.

If the system is using EFI, you get "efi" as output.

sorin@lanfear2:~$ test -d /sys/firmware/efi && echo efi || echo bios
efi
sorin@lanfear2:~$

Sources

https://askubuntu.com/questions/1111045/how-to-check-if-ubuntu-has-booted-in-uefi-mode
https://www.veeam.com/linux-backup-free.html
https://helpcenter.veeam.com/docs/agentforlinux/userguide/recovery_media_create.html