autoboot_command
Option Category #
# SCRIPTING OPTIONS
#
Description This option allows you to add a command that will be run when a system starts. This can be useful for computer systems that require a command to load a software image.
Full Command -autoboot_command <string>
Alt. Command none
Reverse Command none
Example mame64 spectrum batman -autoboot_command "j""""""\n" -autoboot_delay 5

The Sinclair Spectrum used quick keyboard shortcuts to enter commands. "j" is the quick key for Load. Any quotes need to be inside... err... quotes to be shown. Thats why there are six quotes in the command just to create the command Load "". The \n is use for a new line. The delay is there to allow for the system to finish starting up.
mame.ini Command autoboot_command
Command Default none
Argument Format <string>