7.4.1. Environment Variables which control the LNM

This page lists the environment variables that are read directly by the ln_manager.

For message-definition lookup details, see Message Definitions.

LN_MESSAGE_DEFINITION_DIRS

Colon-separated list of additional message-definition root directories.

ln_manager includes these directories in its message-definition search path at startup. The resulting search path is also exported to started processes as part of the default process environment; see environment.

This variable is a global, user-environment based extension mechanism. For instance-local configuration, prefer the add_message_definition_dir directive in the ln-config file.

LN_CONFIG

Path to the user-specific ln_manager config file.

Default is ~/.ln_config.

If the file exists, ln_manager executes it as Python code during startup and uses it to override values from python/links_and_nodes_manager/config.py; see LN Manager user config.

LN_DEBUG

Enable additional ln_manager debug behavior.

When set to a truthy value such as 1 or yes, ln_manager enables extra debug logging and some debug-only startup output.

For the client-side behavior of the same environment variable name, see LN_DEBUG in Environment Variables which affect LN clients.

LN_ARBITER_PORT

Override the fixed TCP port that ln_manager uses to contact the per-host LN daemon arbiter.

The built-in default is 54376.

LN_BUILD_SUBDIR

Source-tree only override for the build directory name used by ln_manager when it tries to locate build artifacts such as libln and ln_daemon.

Default is build.

LN_SRC_TREE_DAEMON_START

Source-tree only override for the default command used to start ln_daemon.

This affects the built-in default before any per-instance or per-host daemon_start_script config overrides are applied.

LN_OPEN_SCOPE_ON_PARAMETER_DOUBLE_CLICK

Controls what happens when the user double-clicks a parameter row in the parameters window.

Default is enabled.

When true, ln_manager requests publication of the parameter topic and opens a scope on the parameter’s .output field.

LN_DAEMON_START

Override the built-in default daemon start command used by ln_manager; see daemon_start_script.

This is intended as a site-local default. It is read during ln_manager startup and used unless the ln-config overrides the daemon start script explicitly.

LN_MANAGER_ASK_SHUTDOWN

defaults to yes

if set to “yes” will ask the user whether to only close the gui and keep the manager process alive when user wants to close the gui window while there are still clients connected. set this to no to disable this question and terminate ln_manager as soon as users closes the gui window.

LNM_TOPICS_DISPLAY_FLAT

Controls the initial topic display mode in the topics tree view.

By default ln_manager shows topics grouped as a tree by their dotted name components.

Set this variable to 1, yes or true to disable that grouping and start with a flat topic list instead.

LN_MANAGER_CONDITIONS_CHECK_FOR_LONG_WAITERS

Internal debug toggle for ln_manager’s Condition helper class.

Default is enabled.

When true, ln_manager starts a background checker thread that can detect and report unusually long waits on these internal condition variables.

LN_TERM_DEBUG

Enable debug logging for ln_manager’s internal terminal/console input parser.

LN_TERM_COLOR

Force colored terminal output handling in ln_manager’s internal terminal code.

This is mainly a debug or compatibility knob for the terminal widget used to show process output and console sessions.

DEBUG_GETSTATE

Enable verbose debug prints while ln_manager serializes and restores internal configuration objects via __getstate__ / __setstate__ style code paths.

LN_CHECK_CB

Enable additional runtime validation of callback signatures in some internal asynchronous helper wrappers.

This is a debugging aid for ln_manager development.

LN_USE_OLD_PYSCOPE

Instead of using new links_and_nodes.scope for plotting signals when double clicking on fields in the PortInspector, use the old OpenGL-based pyscope.

7.4.2. Standard environment variables read by the LNM code

These are not LN-specific, but ln_manager does read them directly.

DISPLAY

Used by the GUI and X11 forwarding code.

ln_manager reports the GUI display to connected sessions, uses it to resolve X11 forwarding targets and cookies, and also includes the display value in the per-display filename used to remember window geometry.

XAUTHORITY

Used to locate the X11 authority database.

If unset, ln_manager falls back to $HOME/.Xauthority; see X11 Connections and Authentication.

HOME

Used for several path defaults, including ~/.ln_config, ~/ln_message_definitions/gen, and the fallback path for XAUTHORITY. It is also propagated in some process-start/X11-forwarding cases.

HOSTNAME

Used only as a last-resort fallback when ln_manager tries to determine the local host name for built-in config variables.

EDITOR

Used as the preferred external editor command in the processes GUI.

Default is /usr/bin/gedit.

7.4.3. Environment Variables which control the LN daemon

LN_DAEMON_NO_HIDE

default no

if set to yes will show each and every received request from the ln_manager connection.