FCEUX offers numerous command line options.
All commands are case sensitive.

ROM name

Plays specified ROM (ROM name must always be put last in command line arguments)

fceux smb.nes
fceux c:\fceux\roms\smb.zip

Play Movie File

Plays a specified movie (.fm2) file. A valid ROM must be specified or movie will not be played.

fceux -playmovie smb.fm2 smb.nes

Read-only Status

Specifies whether a movie will be in “read-only” or “read & write” mode. (Note: a specified movie is not required to be used in conjunction with this command). 1 specifies read only status, 0 specifies read & write.

fceux -readonly 1
fceux -readonly 0 -playmovie smb.fm2 smb.nes
fceux -readonly 1 -playmovie c:\fceux\movies\smb.fm2 c:\fceux\roms\smb.nes

Stop Movie at frame x

Specifies that the movie will automatically stop at the specified frame. (A movie must be specified with -playmovie for this command to work)

fceux -playmovie smb.fm2 -stopframe 10000 smb.nes

Load State

Specifies FCEUX to automatically load a specified savestate file. (Must have a specified ROM for this to work).

fceux -loadstate smb0.fc0 smb.nes
fceux -playmovie smb.fm2 -readonly 0 -loadstate smb0.fc0 smb.nes

Pause Movie After Playback

Sets the “Pause Movie After Playback” switch on/off. 1 sets it to enabled, 0 sets it to disabled.

fceux -stopmovie 1
fceux -playmovie smb.fm2 -readonly 0 - stopmovie 1 smb0.nes

Frame Display Toggle

Toggles whether or not the frame count will be displayed. 1 sets it to on, 0 sets it to off.

fceux -framedisplay 1
fceux -playmovie smb2.fm2 -framedisplay 1 smb0.nes

Input Display Toggle

Toggles whether the movie input will be displayed. 1 sets it to on, 0 sets it to off.

fceux -inputdisplay 1
fceux -playmovie smb2.fm2 -inputdisplay 1 smb0.nes

Allow L+R/U+D

Sets whether or not the game will allow L+R/U+D input (see Input config). 1 enables L+R, 0 disables it.

fceux -allowUDLR 1
fceux -allowUDLR 0 smb0.nes

Enable Background Input

Sets the “Enable Background Input” switch on/off. 1 sets it to enabled, 0 sets it to disabled.

fceux -bginput 0
fceux -playmovie smb.fm2 -readonly 0 -bginput 1 smb0.nes

Use Game Genie

Sets the Game Genie Flag (see Toggle Switches). 1 sets it to enabled, 0 sets it to disabled.

fceux -gg 1
fceux -gg 1 smb0.nes

PAL Emulation

Sets the PAL Emulation Toggle (see Toggle Switches). 1 sets it to enabled, 0 sets it to disabled.
(note: FCEUX will assign PAL emulation automatically if a PAL ROM is loaded)

fceux -pal 1
fceux -pal 1 smb0.nes

Movie Status Icon Toggle

Sets the Status Icon Toggle (see Toggle Switches). 1 turns off the status icon, 0 turns it on.

fceux -noicon 1
fceux -noicon 0 smb0.nes

Clip Left and Right Sides

Sets the Clip Left and Right Sides Toggle (see Video Config). 1 turns on clipping, 0 turns it off.

fceux -clipsides 0 smb0.nes

Allow More than 8 Sprites per Scanline

Sets the 8 Sprites per scanline flag (see Video Config). 1 turns on extra sprites, 0 turns it off.

fceux -no8lim 0 smb0.nes

Disable Speed Throttling

Sets the Disable Speed Throttling When Sound is Disabled flag (see Timing Config). 1 disables throttling, 0 leaves it on.

fceux -nothrottle 0 smb0.nes

Turbo Toggle

Sets the Turbo Toggle. 1 Sets Turbo on, 0 leaves it off.

fceux -turbo 1 smb0.nes

Load Config File

Loads a specified config file rather than the default fceux.cfg
Warning: the config file must be in the base directory. A pathname can NOT be specified in the filename

fceux -cfg fceux-smbconfig.cfg smb.nes

Load Lua Script

Loads a Lua script on startup.

fceux -lua memwatch.lua