CompTIA Linux+ Certification 2026 – 400 Free Practice Questions to Pass the Exam

In Linux, runlevels are essential designations used to manage system states and services. The runlevel that is specifically meant for halting the system is runlevel 0. This runlevel indicates that the system should be shut down safely, terminating all processes and services while ensuring no damage occurs to the file system.

Understanding runlevels helps in system administration and managing how the operating system behaves during different conditions. While other runlevels serve specific purposes, such as single-user mode (runlevel 1), multi-user with networking (runlevel 3), and graphical mode (runlevel 5), runlevel 0’s function is unequivocally to halt the system completely. Using this runlevel ensures that the shutdown process is executed properly, which is crucial for data integrity and system stability.