3c1668da62
The new 'unique' API allows listing all unique field values that a field specified by a field name can take in all entries of the journal. This allows answering queries such as "What units logged to the journal?", "What hosts have logged into the journal?", "Which boot IDs have logged into the journal?". Ultimately this allows implementation of tools similar to lastlog based on journal data. Note that listing these field values will not work for journal files created with older journald, as the field values are not indexed in older files.
131 lines
7.2 KiB
XML
131 lines
7.2 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!--
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This file is part of systemd.
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Copyright 2012 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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-->
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<refentry id="sd-journal">
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<refentryinfo>
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<title>sd-journal</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Lennart</firstname>
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<surname>Poettering</surname>
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<email>lennart@poettering.net</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>sd-journal</refentrytitle>
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<manvolnum>3</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>sd-journal</refname>
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<refpurpose>APIs for submitting and querying log entries to and from the journal</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcsynopsisinfo>#include <systemd/sd-journal.h></funcsynopsisinfo>
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</funcsynopsis>
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<cmdsynopsis>
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<command>pkg-config --cflags --libs libsystemd-journal</command>
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</cmdsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para><filename>sd-journal.h</filename> provides APIs
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to submit and query log entries. The APIs exposed act
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both as client for the
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<citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
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journal service and as parser for the journal files
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on disk.
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</para>
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<para>See
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<citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_stream_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_get_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_add_match</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_seek_head</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_get_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_cutoff_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_get_usage</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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and
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<citerefentry><refentrytitle>sd_journal_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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for more information about the functions
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implemented.</para>
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<para>Command line access for submitting entries to
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the journal is available with the
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<citerefentry><refentrytitle>systemd-cat</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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tool. Command line access for querying entries from
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the journal is available with the
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<citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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tool.</para>
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</refsect1>
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<refsect1>
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<title>Notes</title>
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<para>These APIs are implemented as shared library,
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which can be compiled and linked to with the
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<literal>libsystemd-journal</literal>
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<citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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file.</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<para>
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_stream_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_get_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_add_match</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_seek_head</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_get_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_cutoff_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_get_usage</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_query_unique</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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</para>
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</refsect1>
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</refentry>
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