--- name: "lttng-clear" section: "1" platform: "linux" package: "lttng-tools" version: "2.13.15-2" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/lttng-clear" --- # lttng-clear(1) Clear an LTTng recording session ## NAME lttng-clear - Clear an LTTng recording session ## SYNOPSIS ``` lttng [GENERAL OPTIONS] clear [SESSION | --all] ``` ## DESCRIPTION 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)](/lttng-concepts/7.md) to learn more about recording sessions. The **clear** command clears: Without any option The current recording session. See [**lttng-concepts**(7)](/lttng-concepts/7.md) 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)](/lttng-list/1.md)). See the “Session daemon connection” section of [**lttng**(1)](/lttng/1.md) 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)](/lttng-create/1.md) command), the **clear** command only clears the recording buffers. For a given recording session, if at least one rotation occurred (see [**lttng-concepts**(7)](/lttng-concepts/7.md)), 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)](/lttng-relayd/8.md) 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. ## OPTIONS See [**lttng**(1)](/lttng/1.md) 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)](/lttng-list/1.md), 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. ## EXIT STATUS **0** Success **1** Command error **2** Undefined command **3** Fatal error **4** Command warning (something went wrong during the command) ## ENVIRONMENT **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 **$HOME**. Useful when the Unix user running the commands has a non-writable home directory. **LTTNG\_MAN\_BIN\_PATH** Absolute path to the manual pager to use to read the LTTng command-line help (with [**lttng-help**(1)](/lttng-help/1.md) or with the **--help** option) instead of **/usr/bin/man**. **LTTNG\_SESSION\_CONFIG\_XSD\_PATH** Path to the directory containing the **session.xsd** recording session configuration XML schema. **LTTNG\_SESSIOND\_PATH** Absolute path to the LTTng session daemon binary (see [**lttng-sessiond**(8)](/lttng-sessiond/8.md)) to spawn from the [**lttng-create**(1)](/lttng-create/1.md) command. The **--sessiond-path** general option overrides this environment variable. ## FILES **$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/1.md). [**lttng-create**(1)](/lttng-create/1.md) and [**lttng-set-session**(1)](/lttng-set-session/1.md) set the current recording session. **$LTTNG\_HOME/lttng-traces** Default output directory of LTTng traces in local and snapshot modes. Override this path with the **--output** option of the [**lttng-create**(1)](/lttng-create/1.md) command. **$LTTNG\_HOME/.lttng** Unix user’s LTTng runtime and configuration directory. **$LTTNG\_HOME/.lttng/sessions** Default directory containing the Unix user’s saved recording session configurations (see [**lttng-save**(1)](/lttng-save/1.md) and [**lttng-load**(1)](/lttng-load/1.md)). **/etc/lttng/sessions** Directory containing the system-wide saved recording session configurations (see [**lttng-save**(1)](/lttng-save/1.md) and [**lttng-load**(1)](/lttng-load/1.md)). **Note**\ **$LTTNG\_HOME** defaults to the value of the **HOME** environment variable. ## EXAMPLES **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 ``` ## RESOURCES • LTTng project website \ • LTTng documentation \ • LTTng bug tracker \ • Git repositories \ • GitHub organization \ • Continuous integration \ • Mailing list \ for support and development: **lttng-dev@lists.lttng.org** • IRC channel \: **#lttng** on **irc.oftc.net** ## COPYRIGHT This program is part of the LTTng-tools project. LTTng-tools is distributed under the GNU General Public License version 2 \. See the **LICENSE** \ file for details. ## THANKS Special thanks to Michel Dagenais and the DORSAL laboratory \ 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. ## SEE ALSO [**lttng**(1)](/lttng/1.md), [**lttng-create**(1)](/lttng-create/1.md), [**lttng-concepts**(7)](/lttng-concepts/7.md), [**lttng-relayd**(8)](/lttng-relayd/8.md)