I believe systemd is installed by default.
Here are a couple of commands with example responses from my laptop running
Trisquel 8:
rally@silverbird:~/Desktop$ systemd-analyze
Startup finished in 7.907s (kernel) + 25.403s (userspace) = 33.311s
rally@silverbird:~/Desktop$ systemd-analyze blame
7.601s NetworkManager-wait-online.service
6.136s dev-sda4.device
5.032s apparmor.service
3.711s NetworkManager.service
3.294s postfix.service
3.257s accounts-daemon.service
2.894s lightdm.service
2.645s networking.service
2.441s console-setup.service
1.909s rsyslog.service
1.868s polkitd.service
1.832s grub-common.service
1.587s systemd-fsck@dev-sr0.service
1.549s rc-local.service
1.299s keyboard-setup.service
1.146s irqbalance.service
1.038s systemd-journald.service
.....and lots of other suff taking less and less time to get started.
I noticed tor.service was starting at boot and I haven't been using it so I
did...
rally@silverbird:~/Desktop$ systemctl status tor.service
rally@silverbird:~/Desktop$ sudo systemctl stop tor.service
rally@silverbird:~/Desktop$ sudo systemctl disable tor.service
rally@silverbird:~/Desktop$ systemctl | grep service
will also give a list of services starting up (configured in the /etc/rc.
files)
All the services that start on mine seem necessary. 33 seconds isn't to bad
but if my laptop booted faster that would be nice. The /etc/rc. files allow
for changing the order in which different things boot. Tor had a problem
because I don't hook up to the internet by default and it was trying to.
I know there is a lot more one can do with systemd and systemctl. I'm no
expert.
Here's more info:
https://www.linux.com/learn/understanding-and-using-systemd
