'asapm' is an X11 client which displays a battery status of your
notebook computer equiped with APM (Advanced Power Management) BIOS
or ACPI (Advanced Configuration and Power Interface).
The status displayed consists remaining battery life, an AC line
status, a charging status and a digital readout with (a) Percent
battery remaining and (b) estimated time to dead. If using ACPI this
version can also show the time left to recharge the battery.