What command can be used to see the most slow-to-fast units that have been initialized?

The command that displays the most time-consuming units in the startup process is systemd-analyze blame. When executed, this command provides a list of services or units that were initialized, sorted by the time they took to start. This can be very useful for troubleshooting boot and performance issues, as it allows administrators to identify and address units that are taking longer than expected to load, potentially slowing down the overall boot process.

In contrast, the other options serve different purposes. For example, systemd-analyze report gives a more detailed report of the initialization sequence but does not specifically focus on the slowest units. systemctl overview is not a standard command, and systemctl status primarily provides the status of a specific service rather than analyzing boot performance. Thus, systemd-analyze blame is the most appropriate command for identifying slow-to-fast units during the boot process.