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Command Line Arguments

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Adrien Bertrand edited this page Aug 26, 2026 · 19 revisions

To run CEmu from the command line, use the name of the CEmu program followed by the desired switches. Some switches require an additional argument, as shown below.

CEmu <switches>

Switches

-s <file>, --send <file>

Sends the file to the emulator. This may force a calculator reset. To specify multiple files, use multiple switches, i.e:

-s <file 1> -s <file 2> -s <file n>

-a <file>, --send-arch <file>

Behaves just like the -s switch, but forces files to be stored in the archive.

-m <file>, --send-ram <file>

Behaves just like the -s switch, but forces files to be stored in RAM.

-r <rom file>, --rom <rom file>

Forces CEmu to load a new rom rather than the preconfigured ROM image.

-t <autotester file>, --auto-test <autotester file> [--no-test-dialog]

CEmu forces a calculator reset and executes the file with the AutoTester. --no-test-dialog is optional and suppresses the output of the test statistics from the AutoTester.

--lua-script <script>

Runs a Lua script after the emulator is initialized. This switch may be repeated to run multiple scripts and can also be sent to an existing CEmu process with --id.

-g <settings file>, --settings <settings file>

Uses an external ini file to load the configured settings. This switch is ignored when sending commands to an existing CEmu process.

--no-settings

Does not restore or save settings for this run.

-i <image file>, --image <image file>

CEmu uses the supplied image file to begin emulation.

-d <debug file>, --debug-info <debug file>

Imports the debugging information for the CEmu debugger.

--speed <percentage>

Sets the emulation speed percentage. The value is clamped to the range 0 through 500; the command-line help recommends increments of 10.

-u, --unthrottled

Sets CEmu to run at unthrottled speed after boot.

-n, --no-state

Does not load the saved image state from disk.

--reload-rom

Forces a ROM reload.

--no-reset

Does not reset before sending files or starting an AutoTester run. This may cause emulated crashes if the calculator is not at the home screen.

-c <id>, --id <id>

Command line arguments are routed to the specified CEmu id. This allows you to send commands directly to a current CEmu process. The id is specified in the title of the window; i.e. CEmu | Calculator would have id Calculator.

--ipc-only

Sends commands only to an existing CEmu process with the selected id. If that process is not running, CEmu reports an error instead of creating a new emulator instance. The default id is Calculator when --id is omitted.

--screenshot <file>

Saves a PNG screenshot of the calculator display to the given path. This is an IPC-only command for an already-running process; it is normally used with --id and --ipc-only.

--launch <prgm>

Launch the program specified by prgm.

--keys <sequence>

Presses physical calculator keys from a comma-separated sequence.

Examples:

--keys clear,clear,clear,1,2,3,+,4,5,6,enter
--keys 2nd,mode,delay:250,enter
--keys down:right,delay:100,up:right

The sequence parser is exact and case-sensitive. It does not trim spaces.

Supported sequence steps:

  • keyName or press:keyName: press and release a key
  • delay:<ms>: wait for the specified number of milliseconds
  • hold:keyName:<ms>: hold a key for the specified number of milliseconds, then release it
  • down:keyName: press and hold a key
  • up:keyName: release a key

Accepted key names:

graph, trace, zoom, window, wind, y=, yequ, 2nd, mode, del,
on, sto, ln, log, ^2, sq, -1, inv, math, alpha,
0, 1, 4, 7, comma, sin, apps, xton, xtn,
dot, 2, 5, 8, lpar, cos, prgm, stat,
(-), neg, 3, 6, 9, rpar, tan, vars,
enter, +, add, -, sub, *, mul, /, div, ^, pow, clear, clr,
down, left, right, up

The literal punctuation key names ,, ., (, and ) are also accepted, but , cannot be used directly in --keys because comma separates sequence steps. Use comma instead.

When used with --id, the key sequence is sent to the matching running CEmu process.

--usb <selector|disconnect>

Connects a physical USB device selected by VID:PID or bus#address. Pass disconnect to disconnect the current physical USB device. This can also be sent to an existing CEmu process with --id.

--fullscreen <mode>

Selects the startup display mode: 0 for a normal window, 1 for the full application in fullscreen, or 2 for the calculator LCD in fullscreen. Other values are ignored.

--reset

Deletes CEmu's configuration directory before startup, resetting its configuration files.

-v, --version

Prints the CEmu version and Git revision, then exits.

-?, -h, --help

Lists all available command line arguments, then exits. -? is available on Windows.

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