How to check if the system is in single-user mode in Linux

# Introduction

In this lab, you will learn how to check the operating state of a Linux system, specifically focusing on how to determine if the system is in single-user mode. You will explore traditional runlevels using the `runlevel` and `who -r` commands, and also examine the default system target in modern `systemd` environments using `systemctl get-default`. This hands-on experience will provide you with practical skills for understanding and verifying the system's operational state.