1LTTNG-START(1)                   LTTng Manual                   LTTNG-START(1)
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3
4

NAME

6       lttng-start - Start an LTTng recording session
7

SYNOPSIS

9       lttng [GENERAL OPTIONS] start [SESSION]
10

DESCRIPTION

12       The lttng start command starts a recording session, that is, it
13       activates the LTTng tracers for:
14
15       With the SESSION argument
16           The recording session named SESSION.
17
18       Without the SESSION argument
19           The current recording session (see lttng-concepts(7) to learn more
20           about the current recording session).
21
22       See lttng-concepts(7) to learn more about recording sessions.
23
24       The selected recording session must be inactive (stopped). A recording
25       session is inactive on creation (see lttng-create(1)).
26
27       A start-session trigger action can also start a recording session (see
28       lttng-add-trigger(1)).
29
30       See the “EXAMPLES” section below for usage examples.
31
32       Stop an active recording session with the lttng-stop(1) command.
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OPTIONS

35       See lttng(1) for GENERAL OPTIONS.
36
37   Program information
38       -h, --help
39           Show help.
40
41           This option attempts to launch /usr/bin/man to view this manual
42           page. Override the manual pager path with the LTTNG_MAN_BIN_PATH
43           environment variable.
44
45       --list-options
46           List available command options and quit.
47

EXIT STATUS

49       0
50           Success
51
52       1
53           Command error
54
55       2
56           Undefined command
57
58       3
59           Fatal error
60
61       4
62           Command warning (something went wrong during the command)
63

ENVIRONMENT

65       LTTNG_ABORT_ON_ERROR
66           Set to 1 to abort the process after the first error is encountered.
67
68       LTTNG_HOME
69           Path to the LTTng home directory.
70
71           Defaults to $HOME.
72
73           Useful when the Unix user running the commands has a non-writable
74           home directory.
75
76       LTTNG_MAN_BIN_PATH
77           Absolute path to the manual pager to use to read the LTTng
78           command-line help (with lttng-help(1) or with the --help option)
79           instead of /usr/bin/man.
80
81       LTTNG_SESSION_CONFIG_XSD_PATH
82           Path to the directory containing the session.xsd recording session
83           configuration XML schema.
84
85       LTTNG_SESSIOND_PATH
86           Absolute path to the LTTng session daemon binary (see lttng-
87           sessiond(8)) to spawn from the lttng-create(1) command.
88
89           The --sessiond-path general option overrides this environment
90           variable.
91

FILES

93       $LTTNG_HOME/.lttngrc
94           Unix user’s LTTng runtime configuration.
95
96           This is where LTTng stores the name of the Unix user’s current
97           recording session between executions of lttng(1).  lttng-create(1)
98           and lttng-set-session(1) set the current recording session.
99
100       $LTTNG_HOME/lttng-traces
101           Default output directory of LTTng traces in local and snapshot
102           modes.
103
104           Override this path with the --output option of the lttng-create(1)
105           command.
106
107       $LTTNG_HOME/.lttng
108           Unix user’s LTTng runtime and configuration directory.
109
110       $LTTNG_HOME/.lttng/sessions
111           Default directory containing the Unix user’s saved recording
112           session configurations (see lttng-save(1) and lttng-load(1)).
113
114       /usr/local/etc/lttng/sessions
115           Directory containing the system-wide saved recording session
116           configurations (see lttng-save(1) and lttng-load(1)).
117
118       Note
119           $LTTNG_HOME defaults to the value of the HOME environment variable.
120

EXAMPLES

122       Example 1. Start the current recording session.
123
124               $ lttng start
125
126       Example 2. Start a specific recording session.
127
128               $ lttng start my-session
129

RESOURCES

131       •   LTTng project website <https://lttng.org>
132
133       •   LTTng documentation <https://lttng.org/docs>
134
135       •   LTTng bug tracker <https://bugs.lttng.org>
136
137       •   Git repositories <https://git.lttng.org>
138
139       •   GitHub organization <https://github.com/lttng>
140
141       •   Continuous integration <https://ci.lttng.org/>
142
143       •   Mailing list <https://lists.lttng.org/> for support and
144           development: lttng-dev@lists.lttng.org
145
146       •   IRC channel <irc://irc.oftc.net/lttng>: #lttng on irc.oftc.net
147
149       This program is part of the LTTng-tools project.
150
151       LTTng-tools is distributed under the GNU General Public License
152       version 2 <http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html>.
153       See the LICENSE <https://github.com/lttng/lttng-
154       tools/blob/master/LICENSE> file for details.
155

THANKS

157       Special thanks to Michel Dagenais and the DORSAL laboratory
158       <http://www.dorsal.polymtl.ca/> at École Polytechnique de Montréal for
159       the LTTng journey.
160
161       Also thanks to the Ericsson teams working on tracing which helped us
162       greatly with detailed bug reports and unusual test cases.
163

SEE ALSO

165       lttng(1), lttng-add-trigger(1), lttng-create(1), lttng-enable-event(1),
166       lttng-stop(1), lttng-concepts(7)
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170LTTng 2.13.4                     14 June 2021                   LTTNG-START(1)
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