---
name: "lttng-crash"
section: "1"
platform: "linux"
package: "lttng-tools"
version: "2.13.15-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/lttng-crash"
---

# lttng-crash(1)

Recover and read LTTng trace buffers in the event of a crash

## NAME

lttng-crash - Recover and read LTTng trace buffers in the event of a crash

## SYNOPSIS

```
lttng-crash [--extract=DIR | --viewer=READER] [-verbose]... SHMDIR
```

## DESCRIPTION

The *Linux Trace Toolkit: next generation* \<https://lttng.org/\> is an open-source software package used for correlated tracing of the Linux kernel, user applications, and user libraries.

LTTng consists of Linux kernel modules (for Linux kernel tracing) and dynamically loaded libraries (for user application and library tracing).

The **lttng-crash** command-line tool recovers LTTng trace buffers in the event of a system crash.

**lttng-crash** reads files within the directory *SHMDIR* and does one of:

Without the **--extract** option

Launches a trace reader (see the **--viewer** option) to view the recovered traces.

With the **--extract**=*DIR* option

Extracts the files as uncorrupted LTTng traces to the *DIR* directory.

*SHMDIR* is the directory specified as the argument of the **--shm-path** option of the [**lttng-create**(1)](/lttng-create/1.md) command used to create the recording session for which to recover the traces.

## OPTIONS

- **-x** *DIR*, **--extract**=*DIR*

  Extract recovered traces to the directory *DIR*; do NOT execute any trace reader.

- **-v**, **--verbose**

  Increase verbosity.

  Specify this option up to three times to get more levels of verbosity.

- **-e** *READER*, **--viewer**=*READER*

  Use the trace reader *READER* to read the trace buffers.

  *READER* is the absolute path to the reader command to use, and it can contain command arguments as well. **lttng-crash** passes the trace directory paths to the *READER* command as its last arguments.

  Without this option, **lttng crash** uses [**babeltrace2**(1)](/babeltrace2/1.md) if it’s available. Otherwise, it tries to use [**babeltrace**(1)](/babeltrace/1.md).

### 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.

- **-V**, **--version**

  Show version and quit.

## EXIT STATUS

**0**

Success

**1**

Error

**3**

Fatal error

## RESOURCES

• 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**

## COPYRIGHT

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.

## THANKS

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.

## SEE ALSO

[**babeltrace2**(1)](/babeltrace2/1.md), [**lttng**(1)](/lttng/1.md), [**lttng-create**(1)](/lttng-create/1.md)