Which command would you use to display all running services in a Linux environment?

To display all running services in a Linux environment, using the command systemctl list-units is effective because it directly interacts with the systemd initialization system, which is widely used in modern Linux distributions. The systemctl command is essential for managing system services and units, allowing users to see the status of all currently active services and other units managed by systemd.

When executed with the list-units option, the command specifically lists all units, including services, in the current running state. This enables the user to identify which services are active, inactive, or failed, thus providing a comprehensive overview of the system's service health.

Other options, although they provide useful information in different contexts, do not focus solely on listing services in the same detailed manner. For example, the service --status-all command can show the status of services but does not separate them according to their current state in as much detail as systemctl. The pstree command displays running processes in a tree format but does not specifically target services, and top provides a dynamic real-time view of system processes and resource usage but again lacks the specificity for identifying services.