define the important flags

• journalctl -e: This option shows the most recent journal entries and jumps to the end of the log, allowing you to easily view the latest messages. This is equivalent to using the --pager-end option.

• journalctl -u: This option filters the output to show only the logs for a specific systemd unit. You can specify the unit name as an argument, such as journalctl -u nginx.service to view the logs for the Nginx service. This is equivalent to using the --unit option.

• journalctl -x: This option adds more information to the output, including the full message and the source file and line number where the message was generated. This is equivalent to using the --full option.

summary

Option	Description	Equivalent Double-Dash Flag
-e	Show the most recent journal entries and jump to the end of the log	--pager-end
-u	Filter the output by a specific systemd unit	--unit
-x	Add more information to the output, including the full message and source file/line number	--full

filter

Docs

The --since and --until options accept various time formats:

journalctl --since "2024-06-12 12:00:00" --until "2024-06-12 14:00:00"

journalctl --since "2 hours ago"

Additionally, you can combine these options with other filters like --unit to filter for a specific systemd unit, or -p to filter by log priority level:

journalctl --since "1 hour ago" -u sshd -p err