Description
This option lets you load different versions of BIOS files. For example the NEO-GEO has several different versions of it's BIOS and you can select one here.
Example
mame mslug -bios eur
Command Format
<gamename> -bios <biosname>. You can get the available BIOS names by typing mame <gamename> -listxml and look for the supported BIOSes. The example will load Metal Slug on the NEO-GEO with a european bios.
MAME's Default Setting
default