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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXIT STATUS | ENVIRONMENT | FILES | EXAMPLES | RESOURCES | COPYRIGHT | THANKS | SEE ALSO | COLOPHON |
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LTTNG-CLEAR(1) LTTng Manual LTTNG-CLEAR(1)
lttng-clear - Clear an LTTng recording session
lttng [GENERAL OPTIONS] clear [SESSION | --all]
The lttng clear command clears one or more recording sessions,
that is, it deletes the contents of their recording buffers and of
all their local and streamed trace data.
See lttng-concepts(7) to learn more about recording sessions.
The clear command clears:
Without any option
The current recording session.
See lttng-concepts(7) to learn more about the current
recording session.
With the SESSION argument
The recording session named SESSION.
With the --all option
All the recording sessions of the connected session daemon for
your Unix user, or for all users if your Unix user is root, as
listed in the output of lttng list (see lttng-list(1)).
See the “Session daemon connection” section of lttng(1) to
learn how a user application connects to a session daemon.
If a recording session is configured in snapshot mode (see the
--snapshot option of the lttng-create(1) command), the clear
command only clears the recording buffers.
For a given recording session, if at least one rotation occurred
(see lttng-concepts(7)), the clear command only clears its
recording buffers and its current trace chunk, NOT its archived
trace chunks.
Note
The --disallow-clear option and the
LTTNG_RELAYD_DISALLOW_CLEAR environment variable of
lttng-relayd(8) can disable remote clearing operations. If
LTTng sends recording data over the network for the selected
recording session(s) to an LTTng relay daemon configured as
such, the clear command fails.
See the “EXAMPLES” section below for usage examples.
See lttng(1) for GENERAL OPTIONS.
Recording target
-a, --all
Clear all the recording sessions of your Unix user, or of all
users if your Unix user is root, as listed in the output of
lttng-list(1), instead of the current recording session or the
recording session named SESSION.
Program information
-h, --help
Show help.
This option attempts to launch /usr/bin/man to view this
manual page. Override the manual pager path with the
LTTNG_MAN_BIN_PATH environment variable.
--list-options
List available command options and quit.
0
Success
1
Command error
2
Undefined command
3
Fatal error
4
Command warning (something went wrong during the command)
LTTNG_ABORT_ON_ERROR
Set to 1 to abort the process after the first error is
encountered.
LTTNG_HOME
Path to the LTTng home directory.
Defaults to $HOME.
Useful when the Unix user running the commands has a
non-writable home directory.
LTTNG_LIST_LEGACY
Set to 1 to use the legacy output format (LTTng 2.14 and
earlier) for the lttng-list(1) command instead of the modern
output format.
Note that the legacy output doesn’t show anything related to
features introduced after LTTng 2.14.
LTTNG_MAN_BIN_PATH
Absolute path to the manual pager to use to read the LTTng
command-line help (with lttng-help(1) or with the --help
option) instead of /usr/bin/man.
LTTNG_NO_UTF_8
Set to 1 to NOT emit multi-byte UTF-8 sequences, even if the
locale claims to support it.
LTTNG_SESSION_CONFIG_XSD_PATH
Path to the directory containing the session.xsd recording
session configuration XML schema.
LTTNG_SESSIOND_PATH
Absolute path to the LTTng session daemon binary (see
lttng-sessiond(8)) to spawn from the lttng-create(1) command.
The --sessiond-path general option overrides this environment
variable.
LTTNG_TERM_COLOR
Controls when to emit terminal SGR codes in the output.
The NO_COLOR environment variable overrides this.
One of:
auto (default)
Only emit SGR codes when the standard output is connected
to a color-capable terminal.
always
Always emit SGR codes.
never
Never emit SGR codes.
NO_COLOR
If set and not empty, then it’s equivalent to setting
LTTNG_TERM_COLOR to never.
See NO_COLOR <https://no-color.org/> to learn more.
$LTTNG_HOME/.lttngrc
Unix user’s LTTng runtime configuration.
This is where LTTng stores the name of the Unix user’s current
recording session between executions of lttng(1).
lttng-create(1) and lttng-set-session(1) set the current
recording session.
$LTTNG_HOME/lttng-traces
Default output directory of LTTng traces in local and snapshot
modes.
Override this path with the --output option of the
lttng-create(1) command.
$LTTNG_HOME/.lttng
Unix user’s LTTng runtime and configuration directory.
$LTTNG_HOME/.lttng/sessions
Default directory containing the Unix user’s saved recording
session configurations (see lttng-save(1) and lttng-load(1)).
/usr/local/etc/lttng/sessions
Directory containing the system-wide saved recording session
configurations (see lttng-save(1) and lttng-load(1)).
Note
$LTTNG_HOME defaults to the value of the HOME environment
variable.
Example 1. Clear the current recording session.
$ lttng clear
Example 2. Clear a specific recording session.
$ lttng clear my-session
Example 3. Clear all recording sessions.
See the --all option.
$ lttng clear --all
• LTTng project website <https://lttng.org>
• LTTng documentation <https://lttng.org/docs>
• LTTng bug tracker <https://bugs.lttng.org>
• Git repositories <https://git.lttng.org>
• GitHub organization <https://github.com/lttng>
• Continuous integration <https://ci.lttng.org/>
• Mailing list <https://lists.lttng.org/> for support and
development: lttng-dev@lists.lttng.org
• IRC channel <irc://irc.oftc.net/lttng>: #lttng on irc.oftc.net
• Mastodon <https://mastodon.social/@lttng>
This program is part of the LTTng-tools project.
LTTng-tools is distributed under the GNU General Public License
version 2 <http://www.gnu.org/licenses/old-
licenses/gpl-2.0.en.html>. See the LICENSE
<https://github.com/lttng/lttng-tools/blob/master/LICENSE> file
for details.
Special thanks to Michel Dagenais and the DORSAL laboratory
<http://www.dorsal.polymtl.ca/> at École Polytechnique de Montréal
for the LTTng journey.
Also thanks to the Ericsson teams working on tracing which helped
us greatly with detailed bug reports and unusual test cases.
lttng(1), lttng-create(1), lttng-concepts(7), lttng-relayd(8)
This page is part of the LTTng-Tools (LTTng tools) project.
Information about the project can be found at ⟨http://lttng.org/⟩.
It is not known how to report bugs for this man page; if you know,
please send a mail to man-pages@man7.org. This page was obtained
from the project's upstream Git repository
⟨https://github.com/lttng/lttng-tools.git⟩ on 2026-08-04. (At
that time, the date of the most recent commit that was found in
the repository was 2026-07-30.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
LTTng 2.15.1 14 June 2021 LTTNG-CLEAR(1)
Pages that refer to this page: lttng-concepts(7), lttng-relayd(8)
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HTML rendering created 2026-09-09 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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