neulab/tldr huggingface dataset:
[--permanent] --ipset=ipset --query-entry=entry Return whether the entry has been added to an ipset. Returns 0 if true, 1 otherwise.
Querying an ipset with a timeout will yield an error. Entries are not tracked for ipsets with a timeout.
[--permanent] --ipset=ipset --get-entries List all entries of the ipset.
[--permanent] --ipset=ipset --add-entries-from-file=filename Add a new entries to the ipset from the file. For all entries that are listed in the file but already in the ipset, a warning will be printed.
The file should contain an entry per line. Lines starting with an hash or semicolon are ignored. Also empty lines.
[--permanent] --ipset=ipset --remove-entries-from-file=filename Remove existing entries from the ipset from the file. For all entries that are listed in the file but not in the ipset, a warning will be printed.
--permanent --path-ipset=ipset Print path of the ipset configuration file.
Service Options Options in this section affect only one particular service.
[--permanent] --info-service=service Print information about the service service. The output format is:
service ports: port1 .. protocols: protocol1 .. source-ports: source-port1 .. helpers: helper1 .. destination: ipv1:address1 ..
The following options are only usable in the permanent configuration.
--permanent --new-service=service Add a new permanent and empty service.
Service names must be alphanumeric and may additionally include characters: '_' and '-'.
--permanent --new-service-from-file=filename [--name=service] Add a new permanent service from a prepared service file with an optional name override.
--permanent --delete-service=service Delete an existing permanent service.
--permanent --load-service-defaults=service Load service default settings or report NO_DEFAULTS error.
--permanent --path-service=service Print path of the service configuration file.
--permanent --service=service --set-description=description Set new description to service
--permanent --service=service --get-description Print description for service
--permanent --service=service --set-short=description Set short description to service
--permanent --service=service --get-short Print short description for service
--permanent --service=service --add-port=portid[-portid]/protocol Add a new port to the permanent service.
--permanent --service=service --remove-port=portid[-portid]/protocol Remove a port from the permanent service.
--permanent --service=service --query-port=portid[-portid]/protocol Return wether the port has been added to the permanent service.
--permanent --service=service --get-ports List ports added to the permanent service.
--permanent --service=service --add-protocol=protocol Add a new protocol to the permanent service.
--permanent --service=service --remove-protocol=protocol Remove a protocol from the permanent service.
--permanent --service=service --query-protocol=protocol Return wether the protocol has been added to the permanent service.
--permanent --service=service --get-protocols List protocols added to the permanent service.
--permanent --service=service --add-source-port=portid[-portid]/protocol Add a new source port to the permanent service.
--permanent --service=service --remove-source-port=portid[-portid]/protocol Remove a source port from the permanent service.
--permanent --service=service --query-source-port=portid[-portid]/protocol Return wether the source port has been added to the permanent service.
--permanent --service=service --get-source-ports List source ports added to the permanent service.
--permanent --service=service --add-helper=helper Add a new helper to the permanent service.
--permanent --service=service --remove-helper=helper Remove a helper from the permanent service.
--permanent --service=service --query-helper=helper Return wether the helper has been added to the permanent service.
--permanent --service=service --get-service-helpers List helpers added to the permanent service.
--permanent --service=service --set-destination=ipv:address[/mask] Set destination for ipv to address[/mask] in the permanent service.
--permanent --service=service --remove-destination=ipv Remove the destination for ipv from the permanent service.
--permanent --service=service --query-destination=ipv:address[/mask] Return wether the destination ipv to address[/mask] has been set in the permanent service.
--permanent --service=service --get-destinations List destinations added to the permanent service.
--permanent --service=service --add-include=service Add a new include to the permanent service.
--permanent --service=service --remove-include=service Remove a include from the permanent service.
--permanent --service=service --query-include=service Return wether the include has been added to the permanent service.
--permanent --service=service --get-includes List includes added to the permanent service.
Helper Options Options in this section affect only one particular helper.
[--permanent] --info-helper=helper Print information about the helper helper. The output format is:
helper family: family module: module ports: port1 ..
--permanent --new-helper=helper --module=nf_conntrack_module [--family=ipv4|ipv6] Add a new permanent helper with module and optionally family defined.
Helper names must be alphanumeric and may additionally include characters: '-'.
--permanent --new-helper-from-file=filename [--name=helper] Add a new permanent helper from a prepared helper file with an optional name override.
--permanent --delete-helper=helper Delete an existing permanent helper.
--permanent --load-helper-defaults=helper Load helper default settings or report NO_DEFAULTS error.
--permanent --path-helper=helper Print path of the helper configuration file.
[--permanent] --get-helpers Print predefined helpers as a space separated list.
--permanent --helper=helper --set-description=description Set new description to helper
--permanent --helper=helper --get-description Print description for helper
--permanent --helper=helper --set-short=description Set short description to helper
--permanent --helper=helper --get-short Print short description for helper
--permanent --helper=helper --add-port=portid[-portid]/protocol Add a new port to the permanent helper.
--permanent --helper=helper --remove-port=portid[-portid]/protocol Remove a port from the permanent helper.
--permanent --helper=helper --query-port=portid[-portid]/protocol Return wether the port has been added to the permanent helper.
--permanent --helper=helper --get-ports List ports added to the permanent helper.
--permanent --helper=helper --set-module=description Set module description for helper
--permanent --helper=helper --get-module Print module description for helper
--permanent --helper=helper --set-family=description Set family description for helper
--permanent --helper=helper --get-family Print family description of helper
Internet Control Message Protocol (ICMP) type Options Options in this section affect only one particular icmptype.
[--permanent] --info-icmptype=icmptype Print information about the icmptype icmptype. The output format is:
icmptype destination: ipv1 ..
--permanent --new-icmptype=icmptype Add a new permanent and empty icmptype.
ICMP type names must be alphanumeric and may additionally include characters: '_' and '-'.
--permanent --new-icmptype-from-file=filename [--name=icmptype] Add a new permanent icmptype from a prepared icmptype file with an optional name override.
--permanent --delete-icmptype=icmptype Delete an existing permanent icmptype.
--permanent --load-icmptype-defaults=icmptype Load icmptype default settings or report NO_DEFAULTS error.
--permanent --icmptype=icmptype --set-description=description Set new description to icmptype
--permanent --icmptype=icmptype --get-description Print description for icmptype
--permanent --icmptype=icmptype --set-short=description Set short description to icmptype
--permanent --icmptype=icmptype --get-short Print short description for icmptype
--permanent --icmptype=icmptype --add-destination=ipv Enable destination for ipv in permanent icmptype. ipv is one of ipv4 or ipv6.
--permanent --icmptype=icmptype --remove-destination=ipv Disable destination for ipv in permanent icmptype. ipv is one of ipv4 or ipv6.
--permanent --icmptype=icmptype --query-destination=ipv Return whether destination for ipv is enabled in permanent icmptype. ipv is one of ipv4 or ipv6.
--permanent --icmptype=icmptype --get-destinations List destinations in permanent icmptype.
--permanent --path-icmptype=icmptype Print path of the icmptype configuration file.
Direct Options DEPRECATED The direct interface has been deprecated. It will be removed in a future release. It is superseded by policies, see firewalld.policies(5).
The direct options give a more direct access to the firewall. These options require user to know basic iptables concepts, i.e.  table (filter/mangle/nat/...), chain (INPUT/OUTPUT/FORWARD/...), commands (-A/-D/-I/...), parameters (-p/-s/-d/-j/...) and targets (ACCEPT/DROP/REJECT/...).
Direct options should be used only as a last resort when it's not possible to use for example --add-service=service or --add-rich-rule='rule'.
Warning: Direct rules behavior is different depending on the value of FirewallBackend. See CAVEATS in firewalld.direct(5).
The first argument of each option has to be ipv4 or ipv6 or eb. With ipv4 it will be for IPv4 (iptables(8)), with ipv6 for IPv6 (ip6tables(8)) and with eb for ethernet bridges (ebtables(8)).
[--permanent] --direct --get-all-chains Get all chains added to all tables. This option concerns only chains previously added with --direct --add-chain.
[--permanent] --direct --get-chains { ipv4 | ipv6 | eb } table Get all chains added to table table as a space separated list. This option concerns only chains previously added with --direct --add-chain.
[--permanent] --direct --add-chain { ipv4 | ipv6 | eb } table chain Add a new chain with name chain to table table. Make sure there's no other chain with this name already.
There already exist basic chains to use with direct options, for example INPUT_direct chain (see iptables-save | grep direct output for all of them). These chains are jumped into before chains for zones, i.e. every rule put into INPUT_direct will be checked before rules in zones.
[--permanent] --direct --remove-chain { ipv4 | ipv6 | eb } table chain Remove chain with name chain from table table. Only chains previously added with --direct --add-chain can be removed this way.
[--permanent] --direct --query-chain { ipv4 | ipv6 | eb } table chain Return whether a chain with name chain exists in table table. Returns 0 if true, 1 otherwise. This option concerns only chains previously added with --direct --add-chain.
[--permanent] --direct --get-all-rules Get all rules added to all chains in all tables as a newline separated list of the priority and arguments. This option concerns only rules previously added with --direct --add-rule.
[--permanent] --direct --get-rules { ipv4 | ipv6 | eb } table chain Get all rules added to chain chain in table table as a newline separated list of the priority and arguments. This option concerns only rules previously added with --direct --add-rule.
[--permanent] --direct --add-rule { ipv4 | ipv6 | eb } table chain priority args Add a rule with the arguments args to chain chain in table table with priority priority.
The priority is used to order rules. Priority 0 means add rule on top of the chain, with a higher priority the rule will be added further down. Rules with the same priority are on the same level and the order of these rules is not fixed and may change. If you want to make sure that a rule will be added after another one, use a low priority for the first and a higher for the following.
[--permanent] --direct --remove-rule { ipv4 | ipv6 | eb } table chain priority args Remove a rule with priority and the arguments args from chain chain in table table. Only rules previously added with --direct --add-rule can be removed this way.
[--permanent] --direct --remove-rules { ipv4 | ipv6 | eb } table chain Remove all rules in the chain with name chain exists in table table. This option concerns only rules previously added with --direct --add-rule in this chain.
[--permanent] --direct --query-rule { ipv4 | ipv6 | eb } table chain priority args Return whether a rule with priority and the arguments args exists in chain chain in table table. Returns 0 if true, 1 otherwise. This option concerns only rules previously added with --direct --add-rule.
--direct --passthrough { ipv4 | ipv6 | eb } args Pass a command through to the firewall.  args can be all iptables, ip6tables and ebtables command line arguments. This command is untracked, which means that firewalld is not able to provide information about this command later on, also not a listing of the untracked passthoughs.
[--permanent] --direct --get-all-passthroughs Get all passthrough rules as a newline separated list of the ipv value and arguments.
[--permanent] --direct --get-passthroughs { ipv4 | ipv6 | eb } Get all passthrough rules for the ipv value as a newline separated list of the priority and arguments.
[--permanent] --direct --add-passthrough { ipv4 | ipv6 | eb } args Add a passthrough rule with the arguments args for the ipv value.
[--permanent] --direct --remove-passthrough { ipv4 | ipv6 | eb } args Remove a passthrough rule with the arguments args for the ipv value.
[--permanent] --direct --query-passthrough { ipv4 | ipv6 | eb } args Return whether a passthrough rule with the arguments args exists for the ipv value. Returns 0 if true, 1 otherwise.
Lockdown Options Local applications or services are able to change the firewall configuration if they are running as root (example: libvirt) or are authenticated using PolicyKit. With this feature administrators can lock the firewall configuration so that only applications on lockdown whitelist are able to request firewall changes.
The lockdown access check limits D-Bus methods that are changing firewall rules. Query, list and get methods are not limited.
The lockdown feature is a very light version of user and application policies for firewalld and is turned off by default.
--lockdown-on Enable lockdown. Be careful - if firewall-cmd is not on lockdown whitelist when you enable lockdown you won't be able to disable it again with firewall-cmd, you would need to edit firewalld.conf.
--lockdown-off Disable lockdown.
--query-lockdown Query whether lockdown is enabled. Returns 0 if lockdown is enabled, 1 otherwise.
Lockdown Whitelist Options The lockdown whitelist can contain commands, contexts, users and user ids.
If a command entry on the whitelist ends with an asterisk '*', then all command lines starting with the command will match. If the '*' is not there the absolute command inclusive arguments must match.
Command paths for users are not always the same and depends on the users PATH. Some distributions symlink /bin to /usr/bin in which case it depends on the order they appear in the PATH environment variable.
The context is the security (SELinux) context of a running application or service. To get the context of a running application use ps -e --context.
Warning: If the context is unconfined, then this will open access for more than the desired application.
The lockdown whitelist entries are checked in the following order: 1. context 2. uid 3. user 4. command
[--permanent] --list-lockdown-whitelist-commands List all command lines that are on the whitelist.
[--permanent] --add-lockdown-whitelist-command=command Add the command to the whitelist.
[--permanent] --remove-lockdown-whitelist-command=command Remove the command from the whitelist.
[--permanent] --query-lockdown-whitelist-command=command Query whether the command is on the whitelist. Returns 0 if true, 1 otherwise.
[--permanent] --list-lockdown-whitelist-contexts List all contexts that are on the whitelist.
[--permanent] --add-lockdown-whitelist-context=context Add the context context to the whitelist.
[--permanent] --remove-lockdown-whitelist-context=context Remove the context from the whitelist.
[--permanent] --query-lockdown-whitelist-context=context Query whether the context is on the whitelist. Returns 0 if true, 1 otherwise.
[--permanent] --list-lockdown-whitelist-uids List all user ids that are on the whitelist.
[--permanent] --add-lockdown-whitelist-uid=uid Add the user id uid to the whitelist.
[--permanent] --remove-lockdown-whitelist-uid=uid Remove the user id uid from the whitelist.
[--permanent] --query-lockdown-whitelist-uid=uid Query whether the user id uid is on the whitelist. Returns 0 if true, 1 otherwise.
[--permanent] --list-lockdown-whitelist-users List all user names that are on the whitelist.
[--permanent] --add-lockdown-whitelist-user=user Add the user name user to the whitelist.
[--permanent] --remove-lockdown-whitelist-user=user Remove the user name user from the whitelist.
[--permanent] --query-lockdown-whitelist-user=user Query whether the user name user is on the whitelist. Returns 0 if true, 1 otherwise.
Panic Options --panic-on Enable panic mode. All incoming and outgoing packets are dropped, active connections will expire. Enable this only if there are serious problems with your network environment. For example if the machine is getting hacked in.
This is a runtime only change.
--panic-off Disable panic mode. After disabling panic mode established connections might work again, if panic mode was enabled for a short period of time.
--query-panic Returns 0 if panic mode is enabled, 1 otherwise.
For more examples see http://fedoraproject.org/wiki/FirewallD
Example 1 Enable http service in default zone. This is runtime only change, i.e. effective until restart.
firewall-cmd --add-service=http
Example 2 Enable port 443/tcp immediately and permanently in default zone. To make the change effective immediately and also after restart we need two commands. The first command makes the change in runtime configuration, i.e. makes it effective immediately, until restart. The second command makes the change in permanent configuration, i.e. makes it effective after restart.
firewall-cmd --add-port=443/tcp firewall-cmd --permanent --add-port=443/tcp
On success 0 is returned. On failure the output is red colored and exit code is either 2 in case of wrong command-line option usage or one of the following error codes in other cases:
Note that return codes of --query-* options are special: Successful queries return 0, unsuccessful ones return 1 unless an error occurred in which case the table above applies.
firewall-applet(1), firewalld(1), firewall-cmd(1), firewall-config(1), firewalld.conf(5), firewalld.direct(5), firewalld.dbus(5), firewalld.icmptype(5), firewalld.lockdown-whitelist(5), firewall-offline- cmd(1), firewalld.richlanguage(5), firewalld.service(5), firewalld.zone(5), firewalld.zones(5), firewalld.policy(5), firewalld.policies(5), firewalld.ipset(5), firewalld.helper(5)
firewalld home page: http://firewalld.org
More documentation with examples: http://fedoraproject.org/wiki/FirewallD
Thomas Woerner <twoerner@redhat.com> Developer
Jiri Popelka <jpopelka@redhat.com> Developer
Eric Garver <eric@garver.life> Developer
ADDPART(8)                    System Administration                   ADDPART(8)
addpart - tell the kernel about the existence of a partition
addpart device partition start length
addpart tells the Linux kernel about the existence of the specified partition. The command is a simple wrapper around the "add partition" ioctl.
This command doesnâ€™t manipulate partitions on a block device.
device The disk device.
partition The partition number.
start The beginning of the partition (in 512-byte sectors).
length The length of the partition (in 512-byte sectors).
delpart(8), fdisk(8), parted(8), partprobe(8), partx(8)
The addpart command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.
doc/axel(1)       lightweight command line download accelerator      doc/axel(1)
axel - light command line download accelerator
axel [OPTIONS] url1 [url2] [url...]
Axel is a program that downloads a file from a FTP or HTTP server through multiple connection.  Each connection downloads its own part of the file.
Unlike most other programs, Axel downloads all the data directly to the destination file.  It saves some time at the end because the program does not have to concatenate all the downloaded parts.
Axel supports HTTP, HTTPS, FTP and FTPS protocols.
One argument is required, the URL to the file you want to download. When downloading from FTP, the filename may contain wildcards and the program will try to resolve the full filename. Multiple mirror URLs to an identical file can be specified as well and the program will use all those URLs for the download.
Please note that the program does not check whether the files are equal.
--max-speed=x, -s x Specify a speed (bytes per second) to try to keep the average speed around this speed. This is useful if you do not want the program to suck up all of your bandwidth.
--num-connections=x, -n x Specify an alternative number of connections.
--max-redirect=x Specify an alternative number of redirections to follow when connecting to the server (default is 20).
--output=x, -o x Downloaded data will be put in a local file with the same name, unless you specify a different name using this option. You can specify a directory as well, the program will append the filename.
--search[=x], -S[x] Axel can do a search for mirrors using the filesearching.com search engine. This search will be done if you use this option. You can specify how many different mirrors should be used for the download as well. The search for mirrors can be time-consuming because the program tests every server's speed, and it checks whether the file's still available.
--ipv6, -6 Use the IPv6 protocol only when connecting to the host.
--ipv4, -4 Use the IPv4 protocol only when connecting to the host.
--no-proxy, -N Do not use any proxy server to download the file. Not possible when a transparent proxy is active somewhere, of course.
--insecure, -k Do not verify the SSL certificate. Only use this if you are getting certificate errors and you are sure of the sites authenticity.
--no-clobber, -c Skip download if a file with the same name already exists in the current folder and no state file is found.
--verbose, -v Show more status messages. Use it more than once to see more details.
--quiet, -q No output to stdout.
--alternate, -a This will show an alternate progress indicator. A bar displays the progress and status of the different threads, along with current speed and an estimate for the remaining download time.
--header=x, -H x Add an additional HTTP header. This option should be in the form "Header: Value". See RFC 2616 section 4.2 and 14 for details on the format and standardized headers.
--user-agent=x, -U x Set the HTTP user agent to use. Some websites serve different content based upon this parameter. The default value will include "Axel", its version and the platform.
--help, -h A brief summary of all the options.
--timeout=x, -T x Set I/O and connection timeout
--version, -V Get version information.
Long (double dash) options are supported only if your platform knows about the getopt_long call. If it does not (like *BSD), only the short options can be used.
The program returns 0 when the download was successful, 1 if something really went wrong and 2 if the download was interrupted. If something else comes back, it must be a bug.
The trivial usage to download a file is similar to:
$ axel http://cdimage.debian.org/debian-cd/current/amd64/iso-cd/debian-9.1.0-amd64-netinst.iso
$ axel ftp://ftp.nl.kernel.org/pub/linux/kernel/v2.2/linux-2.2.20.tar.bz2
This will use the Belgian, Dutch, English and German kernel.org mirrors to download a Linux 2.4.17 kernel image.
$ axel ftp://ftp.{be,nl,uk,de}.kernel.org/pub/linux/kernel/v2.4/linux-2.4.17.tar.bz2
This will do a search for the linux-2.4.17.tar.bz2 file on filesearching.com and it'll use the four (if possible) fastest mirrors for the download (possibly including ftp.kernel.org).
$ axel -S4 ftp://ftp.kernel.org/pub/linux/kernel/v2.4/linux-2.4.17.tar.bz2
/etc/axelrc System-wide configuration file.
~/.axelrc Personal configuration file.
These files are not documented in a manpage, but the example file which comes with the program contains enough information. The position of the system-wide configuration file might be different. In source code this example file is at doc/ directory. It's generally installed under /usr/share/doc/axel/examples/, or the equivalent for your system.
Axel was originally written by Wilmer van der Gaast and other authors over time. Please, see the AUTHORS and CREDITS files.
The project homepage is <https://github.com/axel-download- accelerator/axel>
If you intent to help, please, read the CONTRIBUTING.md file. On Debian systems, this file will be available at /usr/share/doc/axel/ directory.
JOURNALCTL(1)                      journalctl                      JOURNALCTL(1)
journalctl - Query the systemd journal
journalctl [OPTIONS...] [MATCHES...]
journalctl may be used to query the contents of the systemd(1) journal as written by systemd-journald.service(8).
If called without parameters, it will show the full contents of the journal, starting with the oldest entry collected.
If one or more match arguments are passed, the output is filtered accordingly. A match is in the format "FIELD=VALUE", e.g. "_SYSTEMD_UNIT=httpd.service", referring to the components of a structured journal entry. See systemd.journal-fields(7) for a list of well-known fields. If multiple matches are specified matching different fields, the log entries are filtered by both, i.e. the resulting output will show only entries matching all the specified matches of this kind. If two matches apply to the same field, then they are automatically matched as alternatives, i.e. the resulting output will show entries matching any of the specified matches for the same field. Finally, the character "+" may appear as a separate word between other terms on the command line. This causes all matches before and after to be combined in a disjunction (i.e. logical OR).
It is also possible to filter the entries by specifying an absolute file path as an argument. The file path may be a file or a symbolic link and the file must exist at the time of the query. If a file path refers to an executable binary, an "_EXE=" match for the canonicalized binary path is added to the query. If a file path refers to an executable script, a "_COMM=" match for the script name is added to the query. If a file path refers to a device node, "_KERNEL_DEVICE=" matches for the kernel name of the device and for each of its ancestor devices is added to the query. Symbolic links are dereferenced, kernel names are synthesized, and parent devices are identified from the environment at the time of the query. In general, a device node is the best proxy for an actual device, as log entries do not usually contain fields that identify an actual device. For the resulting log entries to be correct for the actual device, the relevant parts of the environment at the time the entry was logged, in particular the actual device corresponding to the device node, must have been the same as those at the time of the query. Because device nodes generally change their corresponding devices across reboots, specifying a device node path causes the resulting entries to be restricted to those from the current boot.
Additional constraints may be added using options --boot, --unit=, etc., to further limit what entries will be shown (logical AND).
Output is interleaved from all accessible journal files, whether they are rotated or currently being written, and regardless of whether they belong to the system itself or are accessible user journals.
The set of journal files which will be used can be modified using the --user, --system, --directory, and --file options, see below.
All users are granted access to their private per-user journals. However, by default, only root and users who are members of a few special groups are granted access to the system journal and the journals of other users. Members of the groups "systemd-journal", "adm", and "wheel" can read all journal files. Note that the two latter groups traditionally have additional privileges specified by the distribution. Members of the "wheel" group can often perform administrative tasks.
The output is paged through less by default, and long lines are "truncated" to screen width. The hidden part can be viewed by using the left-arrow and right-arrow keys. Paging can be disabled; see the --no-pager option and the "Environment" section below.
When outputting to a tty, lines are colored according to priority: lines of level ERROR and higher are colored red; lines of level NOTICE and higher are highlighted; lines of level DEBUG are colored lighter grey; other lines are displayed normally.
--no-full, --full, -l Ellipsize fields when they do not fit in available columns. The default is to show full fields, allowing them to wrap or be truncated by the pager, if one is used.
The old options -l/--full are not useful anymore, except to undo --no-full.
-a, --all Show all fields in full, even if they include unprintable characters or are very long. By default, fields with unprintable characters are abbreviated as "blob data". (Note that the pager may escape unprintable characters again.)
-f, --follow Show only the most recent journal entries, and continuously print new entries as they are appended to the journal.
-e, --pager-end Immediately jump to the end of the journal inside the implied pager tool. This implies -n1000 to guarantee that the pager will not buffer logs of unbounded size. This may be overridden with an explicit -n with some other numeric value, while -nall will disable this cap. Note that this option is only supported for the less(1) pager.
-n, --lines= Show the most recent journal events and limit the number of events shown. If --follow is used, this option is implied. The argument is a positive integer or "all" to disable line limiting. The default value is 10 if no argument is given.
--no-tail Show all stored output lines, even in follow mode. Undoes the effect of --lines=.
-r, --reverse Reverse output so that the newest entries are displayed first.
-o, --output= Controls the formatting of the journal entries that are shown. Takes one of the following options:
short is the default and generates an output that is mostly identical to the formatting of classic syslog files, showing one line per journal entry.
short-full is very similar, but shows timestamps in the format the --since= and --until= options accept. Unlike the timestamp information shown in short output mode this mode includes weekday, year and timezone information in the output, and is locale-independent.
short-iso is very similar, but shows ISO 8601 wallclock timestamps.
short-iso-precise as for short-iso but includes full microsecond precision.
short-precise is very similar, but shows classic syslog timestamps with full microsecond precision.
short-monotonic is very similar, but shows monotonic timestamps instead of wallclock timestamps.
short-unix is very similar, but shows seconds passed since January 1st 1970 UTC instead of wallclock timestamps ("UNIX time"). The time is shown with microsecond accuracy.
verbose shows the full-structured entry items with all fields.
export serializes the journal into a binary (but mostly text-based) stream suitable for backups and network transfer (see Journal Export Format[1] for more information). To import the binary stream back into native journald format use systemd-journal- remote(8).
json formats entries as JSON objects, separated by newline characters (see Journal JSON Format[2] for more information). Field values are generally encoded as JSON strings, with three exceptions:
1. Fields larger than 4096 bytes are encoded as null values. (This may be turned off by passing --all, but be aware that this may allocate overly long JSON objects.)
2. Journal entries permit non-unique fields within the same log entry. JSON does not allow non-unique fields within objects. Due to this, if a non-unique field is encountered a JSON array is used as field value, listing all field values as elements.
3. Fields containing non-printable or non-UTF8 bytes are encoded as arrays containing the raw bytes individually formatted as unsigned numbers.
Note that this encoding is reversible (with the exception of the size limit).
json-pretty formats entries as JSON data structures, but formats them in multiple lines in order to make them more readable by humans.
json-sse formats entries as JSON data structures, but wraps them in a format suitable for Server-Sent Events[3].
json-seq formats entries as JSON data structures, but prefixes them with an ASCII Record Separator character (0x1E) and suffixes them with an ASCII Line Feed character (0x0A), in accordance with JavaScript Object Notation (JSON) Text Sequences[4] ("application/json-seq").
cat generates a very terse output, only showing the actual message of each journal entry with no metadata, not even a timestamp. If combined with the --output-fields= option will output the listed fields for each log record, instead of the message.
with-unit similar to short-full, but prefixes the unit and user unit names instead of the traditional syslog identifier. Useful when using templated instances, as it will include the arguments in the unit names.
--output-fields= A comma separated list of the fields which should be included in the output. This has an effect only for the output modes which would normally show all fields (verbose, export, json, json-pretty, json-sse and json-seq), as well as on cat. For the former, the "__CURSOR", "__REALTIME_TIMESTAMP", "__MONOTONIC_TIMESTAMP", and "_BOOT_ID" fields are always printed.
--utc Express time in Coordinated Universal Time (UTC).
--no-hostname Don't show the hostname field of log messages originating from the local host. This switch has an effect only on the short family of output modes (see above).
Note: this option does not remove occurrences of the hostname from log entries themselves, so it does not prevent the hostname from being visible in the logs.
-x, --catalog Augment log lines with explanation texts from the message catalog. This will add explanatory help texts to log messages in the output where this is available. These short help texts will explain the context of an error or log event, possible solutions, as well as pointers to support forums, developer documentation, and any other relevant manuals. Note that help texts are not available for all messages, but only for selected ones. For more information on the message catalog, please refer to the Message Catalog Developer Documentation[5].
Note: when attaching journalctl output to bug reports, please do not use -x.
-q, --quiet Suppresses all informational messages (i.e. "-- Journal begins at ...", "-- Reboot --"), any warning messages regarding inaccessible system journals when run as a normal user.
-m, --merge Show entries interleaved from all available journals, including remote ones.
-b [[ID][±offset]|all], --boot[=[ID][±offset]|all] Show messages from a specific boot. This will add a match for "_BOOT_ID=".
The argument may be empty, in which case logs for the current boot will be shown.
If the boot ID is omitted, a positive offset will look up the boots starting from the beginning of the journal, and an equal-or-less-than zero offset will look up boots starting from the end of the journal. Thus, 1 means the first boot found in the journal in chronological order, 2 the second and so on; while -0 is the last boot, -1 the boot before last, and so on. An empty offset is equivalent to specifying -0, except when the current boot is not the last boot (e.g. because --directory was specified to look at logs from a different machine).
If the 32-character ID is specified, it may optionally be followed by offset which identifies the boot relative to the one given by boot ID. Negative values mean earlier boots and positive values mean later boots. If offset is not specified, a value of zero is assumed, and the logs for the boot given by ID are shown.
The special argument all can be used to negate the effect of an earlier use of -b.
--list-boots Show a tabular list of boot numbers (relative to the current boot), their IDs, and the timestamps of the first and last message pertaining to the boot.
-k, --dmesg Show only kernel messages. This implies -b and adds the match "_TRANSPORT=kernel".
-t, --identifier=SYSLOG_IDENTIFIER Show messages for the specified syslog identifier SYSLOG_IDENTIFIER.
This parameter can be specified multiple times.
-u, --unit=UNIT|PATTERN Show messages for the specified systemd unit UNIT (such as a service unit), or for any of the units matched by PATTERN. If a pattern is specified, a list of unit names found in the journal is compared with the specified pattern and all that match are used. For each unit name, a match is added for messages from the unit ("_SYSTEMD_UNIT=UNIT"), along with additional matches for messages from systemd and messages about coredumps for the specified unit. A match is also added for "_SYSTEMD_SLICE=UNIT", such that if the provided UNIT is a systemd.slice(5) unit, all logs of children of the slice will be shown.
--user-unit= Show messages for the specified user session unit. This will add a match for messages from the unit ("_SYSTEMD_USER_UNIT=" and "_UID=") and additional matches for messages from session systemd and messages about coredumps for the specified unit. A match is also added for "_SYSTEMD_USER_SLICE=UNIT", such that if the provided UNIT is a systemd.slice(5) unit, all logs of children of the unit will be shown.
-p, --priority= Filter output by message priorities or priority ranges. Takes either a single numeric or textual log level (i.e. between 0/"emerg" and 7/"debug"), or a range of numeric/text log levels in the form FROM..TO. The log levels are the usual syslog log levels as documented in syslog(3), i.e.  "emerg" (0), "alert" (1), "crit" (2), "err" (3), "warning" (4), "notice" (5), "info" (6), "debug" (7). If a single log level is specified, all messages with this log level or a lower (hence more important) log level are shown. If a range is specified, all messages within the range are shown, including both the start and the end value of the range. This will add "PRIORITY=" matches for the specified priorities.
--facility= Filter output by syslog facility. Takes a comma-separated list of numbers or facility names. The names are the usual syslog facilities as documented in syslog(3).  --facility=help may be used to display a list of known facility names and exit.
-g, --grep= Filter output to entries where the MESSAGE= field matches the specified regular expression. PERL-compatible regular expressions are used, see pcre2pattern(3) for a detailed description of the syntax.
If the pattern is all lowercase, matching is case insensitive. Otherwise, matching is case sensitive. This can be overridden with the --case-sensitive option, see below.
--case-sensitive[=BOOLEAN] Make pattern matching case sensitive or case insensitive.
-c, --cursor= Start showing entries from the location in the journal specified by the passed cursor.
--cursor-file=FILE If FILE exists and contains a cursor, start showing entries after this location. Otherwise the show entries according the other given options. At the end, write the cursor of the last entry to FILE. Use this option to continually read the journal by sequentially calling journalctl.
--after-cursor= Start showing entries from the location in the journal after the location specified by the passed cursor. The cursor is shown when the --show-cursor option is used.
--show-cursor The cursor is shown after the last entry after two dashes:
-- cursor: s=0639...
The format of the cursor is private and subject to change.
-S, --since=, -U, --until= Start showing entries on or newer than the specified date, or on or older than the specified date, respectively. Date specifications should be of the format "2012-10-30 18:17:16". If the time part is omitted, "00:00:00" is assumed. If only the seconds component is omitted, ":00" is assumed. If the date component is omitted, the current day is assumed. Alternatively the strings "yesterday", "today", "tomorrow" are understood, which refer to 00:00:00 of the day before the current day, the current day, or the day after the current day, respectively.  "now" refers to the current time. Finally, relative times may be specified, prefixed with "-" or "+", referring to times before or after the current time, respectively. For complete time and date specification, see systemd.time(7). Note that --output=short-full prints timestamps that follow precisely this format.
-F, --field= Print all possible data values the specified field can take in all entries of the journal.
-N, --fields Print all field names currently used in all entries of the journal.
--system, --user Show messages from system services and the kernel (with --system). Show messages from service of current user (with --user). If neither is specified, show all messages that the user can see.
-M, --machine= Show messages from a running, local container. Specify a container name to connect to.
-D DIR, --directory=DIR Takes a directory path as argument. If specified, journalctl will operate on the specified journal directory DIR instead of the default runtime and system journal paths.
--file=GLOB Takes a file glob as an argument. If specified, journalctl will operate on the specified journal files matching GLOB instead of the default runtime and system journal paths. May be specified multiple times, in which case files will be suitably interleaved.
--root=ROOT Takes a directory path as an argument. If specified, journalctl will operate on journal directories and catalog file hierarchy underneath the specified directory instead of the root directory (e.g. --update-catalog will create ROOT/var/lib/systemd/catalog/database, and journal files under ROOT/run/journal/ or ROOT/var/log/journal/ will be displayed).
--image=IMAGE Takes a path to a disk image file or block device node. If specified, journalctl will operate on the file system in the indicated disk image. This is similar to --root= but operates on file systems stored in disk images or block devices, thus providing an easy way to extract log data from disk images. The disk image should either contain just a file system or a set of file systems within a GPT partition table, following the Discoverable Partitions Specification[6]. For further information on supported disk images, see systemd-nspawn(1)'s switch of the same name.
--namespace=NAMESPACE Takes a journal namespace identifier string as argument. If not specified the data collected by the default namespace is shown. If specified shows the log data of the specified namespace instead. If the namespace is specified as "*" data from all namespaces is shown, interleaved. If the namespace identifier is prefixed with "+" data from the specified namespace and the default namespace is shown, interleaved, but no other. For details about journal namespaces see systemd-journald.service(8).
--header Instead of showing journal contents, show internal header information of the journal fields accessed.
--disk-usage Shows the current disk usage of all journal files. This shows the sum of the disk usage of all archived and active journal files.
--vacuum-size=, --vacuum-time=, --vacuum-files= Removes the oldest archived journal files until the disk space they use falls below the specified size (specified with the usual "K", "M", "G" and "T" suffixes), or all archived journal files contain no data older than the specified timespan (specified with the usual "s", "m", "h", "days", "months", "weeks" and "years" suffixes), or no more than the specified number of separate journal files remain. Note that running --vacuum-size= has only an indirect effect on the output shown by --disk-usage, as the latter includes active journal files, while the vacuuming operation only operates on archived journal files. Similarly, --vacuum-files= might not actually reduce the number of journal files to below the specified number, as it will not remove active journal files.
--vacuum-size=, --vacuum-time= and --vacuum-files= may be combined in a single invocation to enforce any combination of a size, a time and a number of files limit on the archived journal files. Specifying any of these three parameters as zero is equivalent to not enforcing the specific limit, and is thus redundant.
These three switches may also be combined with --rotate into one command. If so, all active files are rotated first, and the requested vacuuming operation is executed right after. The rotation has the effect that all currently active files are archived (and potentially new, empty journal files opened as replacement), and hence the vacuuming operation has the greatest effect as it can take all log data written so far into account.
--list-catalog [128-bit-ID...] List the contents of the message catalog as a table of message IDs, plus their short description strings.
If any 128-bit-IDs are specified, only those entries are shown.
--dump-catalog [128-bit-ID...] Show the contents of the message catalog, with entries separated by a line consisting of two dashes and the ID (the format is the same as .catalog files).
--update-catalog Update the message catalog index. This command needs to be executed each time new catalog files are installed, removed, or updated to rebuild the binary catalog index.
--setup-keys Instead of showing journal contents, generate a new key pair for Forward Secure Sealing (FSS). This will generate a sealing key and a verification key. The sealing key is stored in the journal data directory and shall remain on the host. The verification key should be stored externally. Refer to the Seal= option in journald.conf(5) for information on Forward Secure Sealing and for a link to a refereed scholarly paper detailing the cryptographic theory it is based on.
--force When --setup-keys is passed and Forward Secure Sealing (FSS) has already been configured, recreate FSS keys.
--interval= Specifies the change interval for the sealing key when generating an FSS key pair with --setup-keys. Shorter intervals increase CPU consumption but shorten the time range of undetectable journal alterations. Defaults to 15min.
--verify Check the journal file for internal consistency. If the file has been generated with FSS enabled and the FSS verification key has been specified with --verify-key=, authenticity of the journal file is verified.
--verify-key= Specifies the FSS verification key to use for the --verify operation.
--sync Asks the journal daemon to write all yet unwritten journal data to the backing file system and synchronize all journals. This call does not return until the synchronization operation is complete. This command guarantees that any log messages written before its invocation are safely stored on disk at the time it returns.
--flush Asks the journal daemon to flush any log data stored in /run/log/journal/ into /var/log/journal/, if persistent storage is enabled. This call does not return until the operation is complete. Note that this call is idempotent: the data is only flushed from /run/log/journal/ into /var/log/journal/ once during system runtime (but see --relinquish-var below), and this command exits cleanly without executing any operation if this has already happened. This command effectively guarantees that all data is flushed to /var/log/journal/ at the time it returns.
--relinquish-var Asks the journal daemon for the reverse operation to --flush: if requested the daemon will write further log data to /run/log/journal/ and stops writing to /var/log/journal/. A subsequent call to --flush causes the log output to switch back to /var/log/journal/, see above.
--smart-relinquish-var Similar to --relinquish-var but executes no operation if the root file system and /var/lib/journal/ reside on the same mount point. This operation is used during system shutdown in order to make the journal daemon stop writing data to /var/log/journal/ in case that directory is located on a mount point that needs to be unmounted.
--rotate Asks the journal daemon to rotate journal files. This call does not return until the rotation operation is complete. Journal file rotation has the effect that all currently active journal files are marked as archived and renamed, so that they are never written to in future. New (empty) journal files are then created in their place. This operation may be combined with --vacuum-size=, --vacuum-time= and --vacuum-file= into a single command, see above.
On success, 0 is returned; otherwise, a non-zero failure code is returned.