In using 'systemctl', what does the 'isolate' command do?

The 'isolate' command in 'systemctl' is used to change the current target of the system immediately. Targets in systemd can be thought of as groups of services that streamline the system's functionality, similar to runlevels in traditional init systems. When you use 'systemctl isolate ', the system will stop all active services that are not part of the specified target and start the services that are part of it, resulting in an immediate change to that target environment.

For example, if you wanted to switch from a multi-user target to a graphical target, executing 'systemctl isolate graphical.target' would stop services that are not required for the graphical environment and start those needed for it, ensuring that only the necessary components are running. This command is particularly useful for quickly switching between operating states without rebooting the system.