runlevel command is used to find the ongoing and previous runlevels on Linux distributions.
Linux users can find the system runlevels by using specified command without argument. The kernerl supports seven runlevels, so the runlevel command identifies the runlevels by numbers. Runlevel command reads the system utmp file to locate and store the runlevel of the system, which is separated by a single space.
The seven runlevels starts with 0 runlevel and ended with 6 runlevel. The complete details of seven runlevels are given below,
0 runlevel – Halts the system
2 & 4 runlevel – Configure the system with advanced users
3 runlevel – Run all typical system services without GUI
5 runlevel – Run typical system services including GUI
6 runlevel – Reboots the system