LINUX COMMAND ATLAS · COMMAND GUIDE

Linux journalctl command

Read systemd journal entries. Use -u to filter by service unit.

systemd

Syntax

Command form

journalctl [OPTIONS...] [MATCHES...]

7 options

Option	What it does
`-u, --unit=UNIT`	Show messages for a systemd unit.
`-f, --follow`	Follow new journal entries.
`-b, --boot[=ID]`	Show entries from the current boot or a selected boot.
`-n, --lines=N`	Show the most recent N entries.
`--since=TIME / --until=TIME`	Restrict entries to a time range.
`-p, --priority=LEVEL`	Filter by priority and more severe levels.
`--no-pager`	Write output directly instead of opening a pager.

3 examples

Read systemd journal entries. Use -u to filter by service unit.

journalctl -u ssh --since today

Show the last 50 SSH unit messages without a pager.

journalctl -u ssh -n 50 --no-pager

Show warning and more severe messages from this boot.

journalctl -b -p warning

Journal access and retention depend on system configuration and user permissions. Avoid sharing logs before checking for secrets or personal data.