lttng-clear(1)
===============
-:revdate: 6 November 2019
+:revdate: 2 April 2020
NAME
----
SYNOPSIS
--------
[verse]
-*lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *clear* [option:--all | 'SESSION']
+*lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *clear* ['SESSION' | option:--all]
DESCRIPTION
-----------
-The `lttng clear` command clears one or more tracing sessions.
+The `lttng clear` command clears one or more tracing sessions, that is,
+it deletes the contents of their tracing buffers and all their local and
+streamed trace data.
If no options are specified, the current tracing session is cleared
(see man:lttng-create(1) for more information about the current
If 'SESSION' is specified, the existing tracing session named 'SESSION'
is cleared.
-If the option:--all option is used, *all* the tracing sessions, as listed
-in the output of `lttng list`, are cleared.
+With the option:--all option, *all* the tracing sessions, as listed in
+the output of `lttng list` (see man:lttng-list(1)), are cleared.
-Clearing a tracing session deletes the contents of the tracing buffers and
-all local or streamed trace data.
+If a tracing session is configured in snapshot mode (see the
+man:lttng-create(1) command's nloption:--snapshot option), only the
+tracing buffers are cleared.
-If a session is configured in snapshot mode, only the tracing buffers are cleared.
+For a given tracing session, if at least one rotation occurred (see
+man:lttng-rotate(1)), only its tracing buffers and its current trace
+chunk are cleared; its archived trace chunks are :not: cleared.
-If at least one rotation occurred, only the tracing buffers and the current
-trace chunks are cleared. Previous trace chunks are not cleared.
+NOTE: The nloption:--disallow-clear option and the
+`LTTNG_RELAYD_DISALLOW_CLEAR` environment variable of
+man:lttng-relayd(8) can disable remote clearing operations. If LTTng
+sends tracing data over the network for 'SESSION' (or for any tracing
+session with the option:--all option) to a relay daemon configured as
+such, `lttng clear` fails.
-Note that a lttng-relayd daemon can be configured to disallow clear operations
-using LTTNG_RELAYD_DISALLOW_CLEAR. Clear commands performed on a streaming
-session utilizing such lttng-relayd daemon will fail.
include::common-cmd-options-head.txt[]
+Target
+~~~~~~
option:-a, option:--all::
- Clear all tracing sessions.
+ Clear all the tracing sessions instead of the current tracing
+ session or the tracing session named 'SESSION'.
+
include::common-cmd-help-options.txt[]
SEE ALSO
--------
+man:lttng-create(1),
man:lttng-rotate(1),
man:lttng-set-session(1),
+man:lttng-relayd(8),
man:lttng(1)