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Command Line Usage

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James Groth edited this page Aug 20, 2026 · 2 revisions

All text on this page applies only to version 0.14.0 and later

Command Line Usage

This page describes functionality that the executable supports on the command line, for example when executing from a shell or a launcher.

Example commands assume the executable is called jgenesis. On Windows you would use jgenesis.exe instead, and if you're using a Linux AppImage build then you'd use the AppImage filename.

Basics

The -f / --file-path arg tells the application to open the specified game immediately at launch, and to exit when you close the game:

jgenesis -f /path/to/rom/file.md

By default the application will keep the GUI window open in the background in case you want to change settings. If you want to suppress the GUI window and only run the game, add the --no-gui arg:

jgenesis -f /path/to/rom/file.md --no-gui

Also by default the application will auto-detect the emulated system based on the file extension and file contents. If you want to explicitly specify the hardware to emulate, add the --hardware arg (full list of possible values below):

jgenesis --hardware Genesis -f /path/to/rom/file.md

Configuration

By default configuration is stored in a user profile-level directory, generally:

  • Windows - C:\Users\$NAME\AppData\Local\jgenesis\
  • Linux - $HOME/.config/jgenesis/

If the application sees a portable.txt file in the same directory as the executable, it will instead store settings in the same directory as the executable. You can toggle this in-app in the Settings > Paths menu.

You can also use the --config arg to pass a path to a custom configuration:

jgenesis -f /path/to/rom/file.md --config /path/to/custom/config.toml

Config Overrides

You can use the --config-override arg to override an individual setting without modifying the settings file, for example:

jgenesis -f /path/to/rom-file.md --config-override genesis.remove_sprite_limits=true

You can use this feature to override any setting that is normally stored in the settings file, except for settings that are part of TOML arrays (e.g. genesis.ym2612_channels_enabled). The full list of settings is not documented here and settings names may change between releases (but generally will not).

Multiple Paths

Sega CD and Sega CD 32X support loading both a cartridge ROM image and a CD-ROM disc image. To specify this on the command line, use the -f arg multiple times, passing the path to the cartridge first and then the path to the CD-ROM image:

jgenesis --hardware SegaCd32X -f /path/to/cartridge.32x -f /path/to/disc.cue

The GUI normally opens a file dialog when you load a Genesis or 32X cartridge that indicates Sega CD support in the header, but this behavior is disabled when -f or --file-path is used, so if you only pass a cartridge path then the emulator will run with no disc in the Sega CD's drive.

Hardware Values

The --hardware arg supports the following values:

  • Genesis
  • SegaCd
  • Sega32X
  • SegaCd32X
  • MasterSystem
  • GameGear
  • Sg1000
  • Nes
  • Snes
  • GameBoy (includes Game Boy Color)
  • GameBoyAdvance
  • PcEngine

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