Provided by: syncthing_0.14.43+ds1-6_amd64 
NAME
syncthing - Syncthing
SYNOPSIS
syncthing [-audit] [-auditfile=<file|-|-->] [-browser-only] [device-id]
[-generate=<dir>] [-gui-address=<address>] [-gui-apikey=<key>]
[-home=<dir>] [-logfile=<filename>] [-logflags=<flags>]
[-no-browser] [-no-console] [-no-restart] [-paths] [-paused]
[-reset-database] [-reset-deltas] [-unpaused] [-upgrade]
[-upgrade-check] [-upgrade-to=<url>] [-verbose] [-version]
DESCRIPTION
Syncthing is an application that lets you synchronize your files across multiple devices. This means the
creation, modification or deletion of files on one machine will automatically be replicated to your other
devices. We believe your data is your data alone and you deserve to choose where it is stored. Therefore
Syncthing does not upload your data to the cloud but exchanges your data across your machines as soon as
they are online at the same time.
OPTIONS
-audit Write events to timestamped file audit-YYYYMMDD-HHMMSS.log.
-auditfile=<file|-|-->
Use specified file or stream ("-" for stdout, "--" for stderr) for audit events, rather than the
timestamped default file name.
-browser-only
Open the web UI in a browser for an already running Syncthing instance.
-device-id
Print device ID to command line.
-generate=<dir>
Generate key and config in specified dir, then exit.
-gui-address=<address>
Override GUI listen address.
-home=<dir>
Set configuration directory. The default configuration directory is $HOME/.config/syncthing
(Unix-like), $HOME/Library/Application Support/Syncthing (Mac) and %LOCALAPPDATA%\Syncthing
(Windows).
-logfile=<filename>
Set destination filename for logging (use "-" for stdout, which is the default option).
-logflags=<flags>
Select information in log line prefix, default 2. The -logflags value is a sum of the following:
• 1: Date
• 2: Time
• 4: Microsecond time
• 8: Long filename
• 16: Short filename
To prefix each log line with date and time, set -logflags=3 (1 + 2 from above). The value 0 is
used to disable all of the above. The default is to show time only (2).
-no-browser
Do not start a browser.
-no-console
Hide the console window. (On Windows only)
-no-restart
Disable the Syncthing monitor process which handles restarts for some configuration changes,
upgrades, crashes and also log file writing (stdout is still written).
-paths Print the paths used for configuration, keys, database, GUI overrides, default sync folder and the
log file.
-paused
Start with all devices and folders paused.
-reset-database
Reset the database, forcing a full rescan and resync. Create .stfolder folders in each sync
folder if they do not already exist. Caution: Ensure that all sync folders which are mountpoints
are already mounted. Inconsistent versions may result if the mountpoint is later mounted and
contains older versions.
-reset-deltas
Reset delta index IDs, forcing a full index exchange.
-unpaused
Start with all devices and folders unpaused.
-upgrade
Perform upgrade.
-upgrade-check
Check for available upgrade.
-upgrade-to=<url>
Force upgrade directly from specified URL.
-verbose
Print verbose log output.
-version
Show version.
DEPRECATED OPTIONS
-gui-apikey=<key>
Override GUI API key (deprecated as of v0.13, to be removed in the future - do not use).
EXIT CODES
0 Success / Shutdown
1 Error
2 Upgrade not available
3 Restarting
4 Upgrading
Some of these exit codes are only returned when running without a monitor process (with environment
variable STNORESTART set). Exit codes over 125 are usually returned by the shell/binary loader/default
signal handler. Exit codes over 128+N on Unix usually represent the signal which caused the process to
exit. For example, 128 + 9 (SIGKILL) = 137.
DEVELOPMENT SETTINGS
The following environment variables modify Syncthing’s behavior in ways that are mostly useful for
developers. Use with care. If you start Syncthing from within service managers like systemd or
supervisor, path expansion may not be supported.
STNODEFAULTFOLDER
Don’t create a default folder when starting for the first time. This variable will be ignored
anytime after the first run.
STGUIASSETS
Directory to load GUI assets from. Overrides compiled in assets.
STTRACE
Used to increase the debugging verbosity in specific or all facilities, generally mapping to a Go
package. Enabling any of these also enables microsecond timestamps, file names plus line numbers.
Enter a comma-separated string of facilities to trace. syncthing -help always outputs an
up-to-date list. The valid facility strings are:
Main and operational facilities:
main Main package.
model The root hub; the largest chunk of the system. File pulling, index transmission and
requests for chunks.
config Configuration loading and saving.
db The database layer.
scanner
File change detection and hashing.
versioner
File versioning.
Networking facilities:
beacon Multicast and broadcast discovery packets.
connections
Connection handling.
dialer Dialing connections.
discover
Remote device discovery requests, replies and registration of devices.
relay Relay interaction.
protocol
The BEP protocol.
nat NAT discovery and port mapping.
pmp NAT-PMP discovery and port mapping.
upnp UPnP discovery and port mapping.
Other facilities:
events Event generation and logging.
http REST API.
sha256 SHA256 hashing package (this facility currently unused).
stats Persistent device and folder statistics.
sync Mutexes. Used for debugging race conditions and deadlocks.
upgrade
Binary upgrades.
all All of the above.
STPROFILER
Set to a listen address such as “127.0.0.1:9090” to start the profiler with HTTP access.
STCPUPROFILE
Write a CPU profile to cpu-$pid.pprof on exit.
STHEAPPROFILE
Write heap profiles to heap-$pid-$timestamp.pprof each time heap usage increases.
STBLOCKPROFILE
Write block profiles to block-$pid-$timestamp.pprof every 20 seconds.
STPERFSTATS
Write running performance statistics to perf-$pid.csv. Not supported on Windows.
STDEADLOCK
Used for debugging internal deadlocks. Use only under direction of a developer.
STDEADLOCKTIMEOUT
Used for debugging internal deadlocks; sets debug sensitivity. Use only under direction of a
developer.
STDEADLOCKTHRESHOLD
Used for debugging internal deadlocks; sets debug sensitivity. Use only under direction of a
developer.
STNORESTART
Equivalent to the -no-restart argument. Disable the Syncthing monitor process which handles
restarts for some configuration changes, upgrades, crashes and also log file writing (stdout is
still written).
STNOUPGRADE
Disable automatic upgrades.
STHASHING
Specify which hashing package to use. Defaults to automatic based on performance. Specify “minio”
(compatibility) or “standard” for the default Go implementation.
GOMAXPROCS
Set the maximum number of CPU cores to use. Defaults to all available CPU cores.
GOGC Percentage of heap growth at which to trigger GC. Default is 100. Lower numbers keep peak memory
usage down, at the price of CPU usage (i.e. performance).
SEE ALSO
syncthing-config(5), syncthing-stignore(5), syncthing-device-ids(7), syncthing-security(7), syncthing-networking(7), syncthing-versioning(7), syncthing-faq(7)
AUTHOR
The Syncthing Authors
COPYRIGHT
2015, The Syncthing Authors