Command Line


  • ✅ 2.2 | ⚠️ 2.1 | ⛔ 2.0 | ⛔ 1.9 ...


Advanced command line usage and environmental variable usage examples. For compiling options, see compiling. For installer options, see deployment.

Environmental Variables

Variable Description Usage
_JAVA_OPTIONS Sets Java command line options for all Java VMs to be picked up.
⚠️ WARNING: Use with caution, impacts all Java instances and applications.
export _JAVA_OPTIONS=-Xmx4096m
QZ_OPTS Sets Java command line options for only QZ Tray to pick up.
(will NOT impact other Java applications)
Since 2.1.3
export QZ_OPTS=-Xmx4096m
export QZ_OPTS=-DtrustedRootCert=custom_cert.pem

💡 Environmental variables will take effect after QZ Tray is restarted.

Windows Environment Variables

Windows environmental variables are often set through Advanced System Settings, Advanced, Environment Variables. Alternatively,through the set|setx command.

setx QZ_OPTS "-Xmx4096m"

... and to revert:

setx QZ_OPTS ""

macOS Environment Variables

macOS environmental variables do not persist; set via defaults write instead:

defaults write io.qz.qz-tray QZ_OPTS -string "-Xmx4096m"`

... and to revert:

defaults delete io.qz.qz-tray QZ_OPTS

💡 For custom branded (white-label) customers, this command will change to defaults write <BUNDLE_ID>.
... where <BUNDLE_ID> is the value returned from java -jar /Applications/ --bundleid

Installer Options

See deployment steps.

Command Line Usage

Since 2.2.0

# Windows
"C:\Program Files\QZ Tray\qz-tray-console.exe" [options]

# Mac
"/Applications/QZ Tray" [options]

# Linux
"/opt/qz-tray/qz-tray" [options]
   java -jar qz-tray.jar [options]

  --help, -h, /?              Display help information and exit.
  --version, -v               Display version information and exit.
  --bundleid, -i              Display Apple bundle identifier and exit.
  --libinfo, -l               Display detailed library version information and exit.

  --allow, --whitelist, -a    Add the specified certificate to allowed.dat.
                                java -jar qz-tray.jar --allow cert.pem
  --block, --blacklist, -b    Add the specified certificate to blocked.dat.
                                java -jar qz-tray.jar --block cert.pem
  --file-allow                Add the specified file.allow entry to for FileIO operations
                              sandboxed to a specified certificate if provided
                                java -jar qz-tray.jar --file-allow /my/file/path [--sandbox "Company Name"]
  --file-remove               Removes the specified file.allow entry from for FileIO operations
                                java -jar qz-tray.jar --file-remove /my/file/path

  --honorautostart, -A        Read and honor any autostart preferences before launching.
  --steal, qz:steal           Ask other running instance to stop so that this instance can take precedence.
  --headless                  Force startup "headless" without graphical interface or interactive components.

  preinstall                  Perform critical pre-installation steps: Stop instances, all other special considerations.
  install                     Copy to the specified destination and preforms platform-specific registration.
                                java -jar qz-tray.jar install --dest /my/install/location [--silent]
  certgen                     Performs certificate generation and registration for proper HTTPS support.
                                java -jar qz-tray.jar certgen [--key key.pem --cert cert.pem] [--pfx cert.pfx --pass 12345] [--host "list;of;hosts"]
  uninstall                   Perform all uninstall tasks: Stop instances, delete files, unregister settings.
  spawn                       Spawn an instance of the specified program as the logged-in user, avoiding starting as the root user if possible.
                                java -jar qz-tray.jar spawn [program params ...]

  jlink                       Download, compress and bundle a Java Runtime
                                java -jar qz-tray.jar jlink [--platform mac|windows|linux] [--arch x64|aarch64]
                                  [--gc hotspot|j9]

For help on a specific command:
  Usage: java -jar qz-tray.jar --help (command)
    --help install
    --help certgen

System Properties

QZ Tray will honor Java system properties via command-line override QZ_OPTS or via Some may also be honored via the user's

Property Description Example
trustedRootCert Overrides the internal licensing certificate by reading the path provided. java -DtrustedRootCert=custom_cert.pem -jar qz-tray.jar ...
tray.notifications Show verbose connect/disconnect notifications in the tray area. java -Dtray.notifications=true -jar qz-tray.jar ...
tray.headless Force QZ Tray into headless mode java -Dtray.headless=true -jar qz-tray.jar ...
tray.monocle Enable/disable monocle JavaFX rendering engine java -Dtray.monocle=false -jar qz-tray.jar ...
tray.strictmode Use strict certificate mode java -Dtray.strictmode=true -jar qz-tray.jar ...
tray.idle.printers When idle, fetch printers in the background java -Dtray.idle.printers=false -jar qz-tray.jar ...
tray.idle.javafx When idle, startup Java FX in the background java -Dtray.javafx=true -jar qz-tray.jar ...
security.file.enabled Enable/disable all File Communications features [true] java -Dsecurity.file.enabled=false -jar qz-tray.jar ...
security.file.strict Enable/disable signing requirements for File Communications features [true] java -Dsecurity.file.strict=false -jar qz-tray.jar ... URL protocols allowed for print, serial, hid, etc [http,https] (Since 2.2.4) java"ftp" -jar qz-tray.jar ...
security.print.tofile Enable/disable printing directly to file paths [false] (Since 2.2.4) java -Dsecurity.print.tofile=true -jar qz-tray.jar ...
security.wss.snistrict Enables strict http/websocket SNI checks [false] (Since 2.2.4) java -Dsecurity.wss.snistrict=true -jar qz-tray.jar ...
security.wss.httpsonly Disables insecure http/websocket ports (e.g. '8182') [false] (Since 2.2.4) java -Dsecurity.wss.httpsonly=true -jar qz-tray.jar ... Influences which physical adapter to bind to by setting the host parameter for http/websocket listening [] (Since 2.2.4) java"" -jar qz-tray.jar ...
tray.file.enabled Enable/disable File IO java -Dtray.file.enabled=false -jar qz-tray.jar ...
tray.file.strict Enable/disable valid signatures for File IO java -Dtray.file.strict=false -jar qz-tray.jar ...
printer.status.jobdata Returns binary job data with printer job events (Since 2.2.2) java -Dprinter.status.jobdata=true -jar qz-tray.jar ...
log.disable Disables logging. (Since 2.2.3) java -Dlog.disable=true -jar qz-tray.jar ...
log.size Modify the log file size before rotating to a new file (Since 2.2.3) java -Dlog.size=2097152 -jar qz-tray.jar ...
log.rotate Modifies the number of rotated log files. (Since 2.2.3) java -Dlog.rotate=9 -jar qz-tray.jar ...
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