>>I _almost_ called it "ac", but I figured that it might confuse
>>people with the "ac" command, and the power doesn't actually have
>>to be AC (for example, a car lighter adapter).
>
>In that case, "external power" and "battery power" spring to my mind.

So, you would vote for filenames like "external_power" and "battery_power",
or "external" and "battery"?

--Ken