Filter by priority error and above

Only err/crit/alert/emerg from current boot; -p takes a range too (e.g. -p warning..err)

journalctl -p err -b --no-pager
tool
journalctl12 commands
tags
journalctldebugtroubleshooting

More journalctl commands

  • Match by raw systemd unit field
    journalctl _SYSTEMD_UNIT=sshd.service --since today

    Trusted unit match by indexed field, unlike -u which also pulls coredumps/PAM noise

  • Combine field filters with OR
    journalctl _PID=1 + _COMM=sshd -o short-iso

    A bare + is a logical OR between match groups; same-field matches within a group are OR'd too

  • Regex grep across messages
    journalctl --grep='oom|out of memory' --case-sensitive=false -b

    PCRE2 match on MESSAGE; pair with -p err to narrow noise. note: scans, not indexed

  • Verbose output with all fields
    journalctl -u <name> -o verbose -n 1

    Dumps every journal field incl. cursor for an entry; -o json-pretty for machine parsing

  • List boots and read previous boot
    journalctl --list-boots && journalctl -b -1 -p warning

    Index past boots, then -b -1 reads the prior boot. note: needs persistent storage

all 12 journalctl commands