sdjournal - Man Page

Provide an interface to capture systemd journal entries.


sdjournal--help ] [ --version ] [ --extcap-interfaces ] [ --extcap-dlts ] [ --extcap-interface=<interface> ] [ --extcap-config ] [ --capture ] [ --fifo=<path to file or pipe> ] [ --start-from=<entry count> ]


sdjournal is an extcap tool that allows one to capture systemd journal entries. It can be used to correlate system events with network traffic.

Supported interfaces:





Print program arguments.


Print program version.


List available interfaces.


Use specified interfaces.


List DLTs of specified interface.


List configuration options of specified interface.


Start capturing from specified interface and write raw packet data to the location specified by --fifo.

--fifo=<path to file or pipe>

Save captured packet to file or send it through pipe.

--start-from=<entry count>

Start from the last <entry count> entries, similar to the "-n" or "--lines" argument for the tail(1) command. Values prefixed with a + sign start from the beginning of the journal, otherwise the count starts from the end. The default value is 10. To include all entries use +0.


To see program arguments:

sdjournal --help

To see program version:

sdjournal --version

To see interfaces:

sdjournal --extcap-interfaces

Only one interface (sdjournal) is supported.

Example output

interface {value=sdjournal}{display=systemd journal capture}

To see interface DLTs:

sdjournal --extcap-interface=sdjournal --extcap-dlts

Example output

dlt {number=147}{name=sdjournal}{display=USER0}

To see interface configuration options:

sdjournal --extcap-interface=sdjournal --extcap-config

Example output

arg {number=0}{call=--start-from}{display=Starting position}{type=string}
    {tooltip=The journal starting position. Values with a leading "+" start from the beginning, similar to the "tail" command}

To capture:

sdjournal --extcap-interface=sdjournal --fifo=/tmp/sdjournal.pcap --capture

To capture all entries since the system was booted:

sdjournal --extcap-interface=sdjournal --fifo=/tmp/sdjournal.pcap --capture --start-from +0


To stop capturing CTRL+C/kill/terminate application.

See Also

wireshark(1), tshark(1), dumpcap(1), extcap(4), tcpdump(1)


sdjournal is part of the Wireshark distribution.  The latest version of Wireshark can be found at

HTML versions of the Wireshark project man pages are available at


Original Author
Gerald Combs <gerald[AT]>