{
    "mode": "man",
    "parameter": "SYSTEMD-CAT",
    "section": "1",
    "url": "https://www.chedong.com/phpMan.php/man/SYSTEMD-CAT/1/json",
    "generated": "2026-06-14T08:02:32Z",
    "synopsis": "",
    "sections": {
        "NAME": {
            "content": "systemd-cat - Connect a pipeline or program's output with the journal\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "",
            "subsections": [
                {
                    "name": "systemd-cat [OPTIONS...] [COMMAND] [ARGUMENTS...]",
                    "content": ""
                },
                {
                    "name": "systemd-cat [OPTIONS...]",
                    "content": ""
                }
            ]
        },
        "DESCRIPTION": {
            "content": "systemd-cat may be used to connect the standard input and output of a process to the journal,\nor as a filter tool in a shell pipeline to pass the output the previous pipeline element\ngenerates to the journal.\n\nIf no parameter is passed, systemd-cat will write everything it reads from standard input\n(stdin) to the journal.\n\nIf parameters are passed, they are executed as command line with standard output (stdout) and\nstandard error output (stderr) connected to the journal, so that all it writes is stored in\nthe journal.\n",
            "subsections": []
        },
        "OPTIONS": {
            "content": "The following options are understood:\n",
            "subsections": [
                {
                    "name": "-h --help",
                    "content": "Print a short help text and exit.\n",
                    "flag": "-h",
                    "long": "--help"
                },
                {
                    "name": "--version",
                    "content": "Print a short version string and exit.\n",
                    "long": "--version"
                },
                {
                    "name": "-t --identifier=",
                    "content": "Specify a short string that is used to identify the logging tool. If not specified, no\nidentification string is written to the journal.\n",
                    "flag": "-t"
                },
                {
                    "name": "-p --priority=",
                    "content": "Specify the default priority level for the logged messages. Pass one of \"emerg\", \"alert\",\n\"crit\", \"err\", \"warning\", \"notice\", \"info\", \"debug\", or a value between 0 and 7\n(corresponding to the same named levels). These priority values are the same as defined\nby syslog(3). Defaults to \"info\". Note that this simply controls the default, individual\nlines may be logged with different levels if they are prefixed accordingly. For details,\nsee --level-prefix= below.\n",
                    "flag": "-p"
                },
                {
                    "name": "--stderr-priority=",
                    "content": "Specifies the default priority level for messages from the process's standard error\noutput (stderr). Usage of this option is the same as the --priority= option, above, and\nboth can be used at once. When both are used, --priority= will specify the default\npriority for standard output (stdout).\n\nIf --stderr-priority= is not specified, messages from stderr will still be logged, with\nthe same default priority level as stdout.\n\nAlso, note that when stdout and stderr use the same default priority, the messages will\nbe strictly ordered, because one channel is used for both. When the default priority\ndiffers, two channels are used, and so stdout messages will not be strictly ordered with\nrespect to stderr messages - though they will tend to be approximately ordered.\n"
                },
                {
                    "name": "--level-prefix=",
                    "content": "Controls whether lines read are parsed for syslog priority level prefixes. If enabled\n(the default), a line prefixed with a priority prefix such as \"<5>\" is logged at priority\n5 (\"notice\"), and similar for the other priority levels. Takes a boolean argument.\n"
                }
            ]
        },
        "EXIT STATUS": {
            "content": "On success, 0 is returned, a non-zero failure code otherwise.\n",
            "subsections": []
        },
        "EXAMPLES": {
            "content": "",
            "subsections": [
                {
                    "name": "Example 1. Invoke a program",
                    "content": "This calls /bin/ls with standard output and error connected to the journal:\n\n# systemd-cat ls\n"
                },
                {
                    "name": "Example 2. Usage in a shell pipeline",
                    "content": "This builds a shell pipeline also invoking /bin/ls and writes the output it generates to the\njournal:\n\n# ls | systemd-cat\n\nEven though the two examples have very similar effects the first is preferable since only one\nprocess is running at a time, and both stdout and stderr are captured while in the second\nexample, only stdout is captured.\n"
                }
            ]
        },
        "SEE ALSO": {
            "content": "systemd(1), systemctl(1), logger(1)\n\n\n\nsystemd 249                                                                           SYSTEMD-CAT(1)",
            "subsections": []
        }
    },
    "summary": "systemd-cat - Connect a pipeline or program's output with the journal",
    "flags": [
        {
            "flag": "-h",
            "long": "--help",
            "arg": null,
            "description": "Print a short help text and exit."
        },
        {
            "flag": "",
            "long": "--version",
            "arg": null,
            "description": "Print a short version string and exit."
        },
        {
            "flag": "-t",
            "long": null,
            "arg": null,
            "description": "Specify a short string that is used to identify the logging tool. If not specified, no identification string is written to the journal."
        },
        {
            "flag": "-p",
            "long": null,
            "arg": null,
            "description": "Specify the default priority level for the logged messages. Pass one of \"emerg\", \"alert\", \"crit\", \"err\", \"warning\", \"notice\", \"info\", \"debug\", or a value between 0 and 7 (corresponding to the same named levels). These priority values are the same as defined by syslog(3). Defaults to \"info\". Note that this simply controls the default, individual lines may be logged with different levels if they are prefixed accordingly. For details, see --level-prefix= below."
        },
        {
            "flag": "",
            "long": null,
            "arg": null,
            "description": "Specifies the default priority level for messages from the process's standard error output (stderr). Usage of this option is the same as the --priority= option, above, and both can be used at once. When both are used, --priority= will specify the default priority for standard output (stdout). If --stderr-priority= is not specified, messages from stderr will still be logged, with the same default priority level as stdout. Also, note that when stdout and stderr use the same default priority, the messages will be strictly ordered, because one channel is used for both. When the default priority differs, two channels are used, and so stdout messages will not be strictly ordered with respect to stderr messages - though they will tend to be approximately ordered."
        },
        {
            "flag": "",
            "long": null,
            "arg": null,
            "description": "Controls whether lines read are parsed for syslog priority level prefixes. If enabled (the default), a line prefixed with a priority prefix such as \"<5>\" is logged at priority 5 (\"notice\"), and similar for the other priority levels. Takes a boolean argument."
        }
    ],
    "examples": [
        "This calls /bin/ls with standard output and error connected to the journal:",
        "# systemd-cat ls",
        "This builds a shell pipeline also invoking /bin/ls and writes the output it generates to the",
        "journal:",
        "# ls | systemd-cat",
        "Even though the two examples have very similar effects the first is preferable since only one",
        "process is running at a time, and both stdout and stderr are captured while in the second",
        "example, only stdout is captured."
    ],
    "see_also": [
        {
            "name": "systemd",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/systemd/1/json"
        },
        {
            "name": "systemctl",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/systemctl/1/json"
        },
        {
            "name": "logger",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/logger/1/json"
        }
    ],
    "tldr": {
        "source": "official",
        "description": "Connect a pipeline or program's output streams with the systemd journal.",
        "examples": [
            {
                "description": "Write the output of the specified command to the journal (both output streams are captured)",
                "command": "systemd-cat {{command}}"
            },
            {
                "description": "Write the output of a pipeline to the journal (`stderr` stays connected to the terminal)",
                "command": "{{command}} | systemd-cat"
            },
            {
                "description": "Use the specified identifier (default: `cat` when reading from a pipeline, executable name otherwise)",
                "command": "{{command}} | systemd-cat {{-t|--identifier}} {{id}}"
            },
            {
                "description": "Use the specified default priority level for all logged messages",
                "command": "systemd-cat {{-p|--priority}} {{emerg|alert|crit|err|warning|notice|info|debug}} {{command}}"
            },
            {
                "description": "Use the specified default priority level for the logged messages from the command's `stderr`",
                "command": "systemd-cat --stderr-priority {{emerg|alert|crit|err|warning|notice|info|debug}} {{command}}"
            }
        ]
    }
}