How does the restart command function when the designated unit is already stopped?

The restart command is designed to perform two operations: stopping a service or unit that is currently running and then starting it again. When the designated unit is already stopped, the behavior may vary slightly based on the implementation of the restart command in the specific Linux distribution or the service management tool in use, such as systemd.

In this case, if the unit is already stopped, the command will not need to stop it again because it's not running. Therefore, its main action will be to initiate and start the unit. This action is often treated as a no-op operation followed by the start action, allowing the unit to begin operation successfully. Thus, the restart command effectively behaves as a start command in such scenarios, initiating the unit without generating any errors or redundant stop commands.