lttng-start(1)

1LTTNG-START(1)                   LTTng Manual                   LTTNG-START(1)
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NAME

6       lttng-start - Start an LTTng recording session
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SYNOPSIS

9       lttng [GENERAL OPTIONS] start [SESSION]
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DESCRIPTION

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

35       See lttng(1) for GENERAL OPTIONS.
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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.
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45       --list-options
46           List available command options and quit.
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EXIT STATUS

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

65       LTTNG_ABORT_ON_ERROR
66           Set to 1 to abort the process after the first error is encountered.
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68       LTTNG_HOME
69           Path to the LTTng home directory.
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71           Defaults to $HOME.
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73           Useful when the Unix user running the commands has a non-writable
74           home directory.
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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.
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81       LTTNG_SESSION_CONFIG_XSD_PATH
82           Path to the directory containing the session.xsd recording session
83           configuration XML schema.
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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.
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89           The --sessiond-path general option overrides this environment
90           variable.
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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.
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100       $LTTNG_HOME/lttng-traces
101           Default output directory of LTTng traces in local and snapshot
102           modes.
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104           Override this path with the --output option of the lttng-create(1)
105           command.
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107       $LTTNG_HOME/.lttng
108           Unix user’s LTTng runtime and configuration directory.
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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)).
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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)).
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118       Note
119           $LTTNG_HOME defaults to the value of the HOME environment variable.
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EXAMPLES

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

131       •   LTTng project website <https://lttng.org>
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133       •   LTTng documentation <https://lttng.org/docs>
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135       •   LTTng bug tracker <https://bugs.lttng.org>
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137       •   Git repositories <https://git.lttng.org>
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139       •   GitHub organization <https://github.com/lttng>
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141       •   Continuous integration <https://ci.lttng.org/>
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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
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COPYRIGHT

149       This program is part of the LTTng-tools project.
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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.
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161       Also thanks to the Ericsson teams working on tracing which helped us
162       greatly with detailed bug reports and unusual test cases.
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