Some things about the systemd of Linux

1. Output the unit that failed to run:

Systemctl--failed

2. All the unit files are stored in both the/usr/lib/systemd/system/and/etc/systemd/system/directories, but the latter are of higher priority. Systemctl List-unit-files can list all the units.

3. Check whether the unit is configured to start automatically: Systemctl is-enabled < unit name >

4. There is a unit suffix name is target, boot boot into the goal is default.target, this file by default is the Graphical.target symbolic link.

5. SYSTEMD provides its own log system, called Journal, using the Journalctl command can view the log, after the counter-check, the command is from the SYSTEMD this package, popularly speaking is SYSTEMD comes with.

Journal configuration file:/etc/systemd/journald.conf, which can define the location of the log file storage, the default is/var/log/journal, the directory is part of the SYSTEMD software package, if deleted, SYSTEMD will not It is created automatically until the next upgrade so the SYSTEMD software package is created, and if the directory is missing, Systemd writes the log to/run/systemd/journal, which means that the log disappears after the boot.

6. Show all logs after this startup: Journalctl-b

Some things about the systemd of Linux