journalctl Filter Builder

v1.0.0

Compose journalctl filter flags visually — units, priority, time windows, kernel ring.

Unit / Service

Priority (--priority)

Since

Until

Grep pattern

Last N lines (-n)

Follow (-f)

Output format (-o)

journalctl Command

journalctl -u nginx.service -p 3 --since "1 hour ago" -n 100

# Common shortcuts:
# journalctl -u nginx -f              # follow nginx logs
# journalctl -p err -b                 # errors since last boot
# journalctl --since "5 minutes ago"   # last 5 minutes
# journalctl -o json-pretty | jq .     # pretty JSON