<html>
    <head>
      <base href="https://bugs.freedesktop.org/" />
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - journalctl misbehaves with --lines"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=84867">84867</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>journalctl misbehaves with --lines
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>systemd
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>unspecified
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>Other
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>critical
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>medium
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>general
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>systemd-bugs@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>marius.vollmer@redhat.com
          </td>
        </tr>

        <tr>
          <th>QA Contact</th>
          <td>systemd-bugs@lists.freedesktop.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>systemd-215-14.fc21.x86_64

With this set of journal files

    files.cockpit-project.org/files/journal-bug.tar.xz

I can see this behavior:

$ journalctl -D ./journal.bug/ _SYSTEMD_UNIT=accounts-daemon.service | tail -5
Oct 10 09:44:07 f21.cockpit.lan accounts-daemon[1178]: started daemon version
0.6.38
Oct 10 09:57:47 f21.cockpit.lan accounts-daemon[1178]: request by
system-bus-name::1.12 [/usr/libexec/cockpitd pid:1169 uid:1000]: delete user
'junior' (1001)
Oct 10 09:57:47 f21.cockpit.lan userdel[4245]: delete user 'junior'
Oct 10 09:57:47 f21.cockpit.lan userdel[4245]: removed group 'junior' owned by
'junior'
Oct 10 09:57:47 f21.cockpit.lan userdel[4245]: removed shadow group 'junior'
owned by 'junior'

$ journalctl -D ./journal.bug/ _SYSTEMD_UNIT=accounts-daemon.service
--lines=100 | tail -5
Oct 08 10:35:52 f21.cockpit.lan accounts-daemon[1255]: started daemon version
0.6.38
-- Reboot --
Oct 08 14:08:00 f21.cockpit.lan accounts-daemon[1937]: started daemon version
0.6.38
-- Reboot --
Oct 10 09:44:07 f21.cockpit.lan accounts-daemon[1178]: started daemon version
0.6.38

That is, when using --lines, journalctl omits some lines at the end. 
Erroneously omitting journal lines is critical, I think.

(The journal files might be corruped since they come from a machine that is
being mistreated quite badly, but journalctl doesn't give any sign of that.)</pre>
        </div>
      </p>
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