Systemd

systemd is a Linux initialization system and service manager introduced in 2010 and adopted by default in RHEL 7.0, that includes features like:

• On-demand starting of daemons
• Inhibitor Locks which allows to block or delay system sleep and shutdown requests from the user
• Mount and automount point maintenance (systemd-mount, systemd-umount )
• Snapshot support
• Processes tracking using Linux control groups (systemd-cglssystemd-cgtop)
• Logging daemon, see journalctl and systemd-cat

Config files:

• /etc/systemd/logind.conf

Systemd components of daemons and binaries:

• systemd: systemctl
• systemd-journald: journalctl
• systemd-logind: loginctl
• systemd-networkd: networkctl, netplan
• systemd-timesyncd
• systemd-resolved: systemd-resolve, hostnamectl
• systemd-udevd

/lib/systemd/systemd-fsck

See also

• macOS: launctl
• systemd, daemontools, runit and https://en.wikipedia.org/wiki/Process_supervision
• cron, crontab, systemctl list-timers, anacron, Kubernetes scheduler, Systemd services, CronJobsStack, cron.schedule, crontab -l, 0x004b, at, /etc/cron.deny, /etc/cron.allow, /etc/crontab, /var/spool/cron/crontabs/
• elogind

https://www.freedesktop.org/wiki/Software/systemd/inhibit/

http://manpages.ubuntu.com/manpages/bionic/man1/systemd-inhibit.1.html

https://www.freedesktop.org/software/systemd/man/systemd.mount.html

https://wiki.ubuntu.com/DebuggingSystemd