The systemd-analyze command is a utility used to investigate systemd boot performance. The blame subcommand specifically prints a list of all running units, ordered by the time they took to initialize during startup. This directly answers the administrator's need to see how long a specific service, such as NetworkManager, took to start. It provides a clear, human-readable output for performance analysis of individual services.

A. resolvectl is used to manage network name resolution and DNS settings, not to analyze service start times.

B. journalctl is used to query and display logs from the systemd journal, but it doesn't directly provide a performance analysis of start times.

C. systemctl daemon-reload reloads the systemd manager configuration files, which is not related to viewing service start-up durations.

1. Red Hat

"Red Hat Enterprise Linux 8 Documentation

" Chapter 10. Managing services with systemd

Section 10.6.2. Determining how long the boot process takes. The documentation states

"To list all running units and the time they took to initialize

type: systemd-analyze blame".

2. Freedesktop.org

"systemd-analyze man page

" The blame command is described as: "Prints a list of all running units

ordered by the time they took to initialize."

3. University of Washington

"CSE/EE 474: Introduction to Embedded Systems

" Lab 3: Linux and systemd. The courseware instructs students to use systemd-analyze blame to "see what services are taking the longest to start."