Command-Line Options

You never need the command line for everyday use. It's for the times something gets in the way: to check which version is installed, to start KafkIO with debug logging, or to reset a preference that stops it from starting properly.

Starting KafkIO from a terminal

Run the KafkIO program with the options after it. Where it is depends on how you installed it (Installation & Updates):

On macOS and Linux, whatever KafkIO prints (help, version, messages about reset preferences, and its log while it runs) appears in the terminal.

On Windows, KafkIO.exe is a windowed program, so Command Prompt and PowerShell don't show what it prints. To see the output, run run.bat instead, from the same folder as KafkIO.exe: it passes your options on to KafkIO, shows its output in the console window, and waits for a key press when KafkIO exits. Options that don't need output, such as --debug or --delpr, work directly with KafkIO.exe too.

"C:\Program Files\KafkIO\run.bat" --version

Options

Each option has a short and a long form; they do the same thing.

KafkIO's own help looks like this (it currently prints it twice, as it does the version):

usage: KafkIO [OPTIONS]

Options: [-b] [-d <KEY1[,KEY2][,KEYn] | all>] [-h] [-v] [-x]
 -b,--blank                              Do not open any files at startup
 -d,--delpr <KEY1[,KEY2][,KEYn] | all>   Reset preferences: '-d mainFontSize,newline' or '-d all'
 -h,--help                               Display help on command line options
 -v,--version                            Display version
 -x,--debug                              Run in debug log mode

Please report issues at https://www.kafkio.com/contact

Short options can be combined (-xv is -x -v), and a long option can be shortened as long as it's unambiguous (--deb). An option KafkIO doesn't know, or -d without a value, makes it print the help above and exit without opening. Anything that isn't an option (a file name, for example) is ignored.

Debug logging

Use --debug when the normal log doesn't say enough to explain a problem, such as a connection that times out for no clear reason. Close KafkIO first (see Running more than one instance), then:

"C:\Program Files\KafkIO\KafkIO.exe" --debug
/Applications/KafkIO.app/Contents/MacOS/KafkIO --debug
/opt/kafkio/bin/KafkIO --debug

Debug logs grow quickly, so only use it while you reproduce the problem. Log files and debug mode explains where the logs go and how to send them with a bug report. The portable versions also include run_debug.bat (Windows) or run_debug.sh (macOS, Linux), which start KafkIO with --debug plus extra JavaFX graphics logging and save the output to a file.

Resetting preferences

--delpr is for a setting that stops KafkIO from starting or makes it unusable, such as an unreachable proxy or a font size too big to work with. Close KafkIO, then pass the preference keys (the names in Show preferences) or all:

"C:\Program Files\KafkIO\KafkIO.exe" --delpr mainFontSize,overrideDefaultFontSize
/opt/kafkio/bin/KafkIO --delpr useProxy
/Applications/KafkIO.app/Contents/MacOS/KafkIO --delpr all

Your clusters aren't affected. --delpr all is the same as the Reset preferences button. A key that isn't stored (misspelt, or already at its default) is skipped with "Unknown preference key". The language, proxy, Kerberos and certificate settings are applied before the reset runs, so after resetting one of those, restart KafkIO once more. Managing Preferences has the details, including a Memory Stick Mode caveat.

Java system properties

Any argument of the form -Dname=value is set as a Java system property before KafkIO starts (an argument without = is reported and ignored). You rarely need this; the main use is working around graphics problems (blank or flickering windows, drawing glitches) by switching JavaFX to software rendering:

"C:\Program Files\KafkIO\KafkIO.exe" -Dprism.order=sw

It lasts until you quit. If it fixes the problem, please report it, with your graphics card and system.

Running more than one instance

Only one copy of KafkIO runs at a time for each user on a computer. If you start KafkIO while it's already running (from the menu, a shortcut or a terminal), the new copy doesn't open a second window: it brings the running one to the front, restoring it if it's minimised and giving it a short shake so you can spot it, then exits. Each user account on a shared machine (a terminal server, for example) can run its own copy.

This matters for the command line, because the new copy processes its options before it notices the running one and hands over:

• --debug has no effect: the running copy keeps logging as it was.
• --delpr changes preferences underneath the running copy, which still holds the old values in memory and may write them back.
• --help and --version are fine: they exit before the check.

So close KafkIO before starting it with options. To work with several clusters at once, you don't need a second copy: connect them all in one window and open several cluster tabs.

KafkIO detects the running copy with lock files in the mb folder of its data folder (for example %LOCALAPPDATA%\com.certak\kafkio\mb on Windows). The operating system releases the locks when KafkIO exits, even after a crash, so they never need deleting by hand.

Related

• Log files and debug mode
• Resetting preferences
• Installation & Updates
• File Locations