# dpkg -l|grep acpi
ii acpi 0.09-1 displays information on ACPI devices
ii acpi-support 0.90 a collection of useful events for acpi
ii acpid 1.0.4-5ubuntu4 Utilities for using ACPI power management
ii acpitool 0.4.4-1 a small, convenient command-line ACPI client
# ps -ax|grep acpi
Warning: bad ps syntax, perhaps a bogus '-'? See http://procps.sf.net/faq.html
9 ? S< 0:00 [kacpid]
10 ? S< 0:00 [kacpi_notify]
3653 ? Ss 0:00 /usr/sbin/acpid -c /etc/acpi/events -s /var/run/acpid.socket
3944 ? S 0:00 /usr/lib/hal/hald-addon-acpi
5413 pts/1 S+ 0:00 grep acpi