It provides a.o. information on battery status, AC adapter presence, thermal reading, etc. This command is most useful on laptops with an ACPI compliant BIOS and a Linux kernel, preferably from the 2.6 series, with ACPI enabled.
acpitool also allows the machine to be put into standby. If your laptop is a Toshiba, it also allows you to set the LCD brighness level and toggle the fan on/off.
| -a | Show AC adapter presence |
| -b | Show battery status information, available batteries only. |
| -B | Show battery status information, all info on all batteries. |
| -e | Show just about everything : more info on the batteries, ACPI version, kernel version, CPU, . . . |
| -f | Show fan status. |
| -F x | Force the fan on (x=1) or off (x=0). Works only on Toshiba laptops. Requires write access to /proc/acpi/toshiba/fan |
| -h | Show help text. |
| -l x | Set LCD brightness level to x, where x is in the range 0..7. Works only on Toshiba laptops.
Requires write access to /proc/acpi/tochiba/lcd. Illegal values for x will result in the value being set to either 0 or 7. |
| -s | Put the machine into sleep state S3, if possible. Requires write access to /proc/acpi/sleep (kernel 2.4.x) or /sys/power/state (kernel 2.6.x). |
| -S | Put the machine into sleep state S4, if possible. Requires write access to /proc/acpi/sleep (kernel 2.4.x) or /sys/power/state (kernel 2.6.x). |
| -t | Show thermal zone(s) information. |
| -T | Show supported Toshiba ACPI extensions, currently being LCD brightness level, video out routing (what display is the video chip sending to) and fan status (on/off, forced or not). |
| -v | Be more verbose when something is not found. Makes sense only when used in conjunction with other options. |
| -V | Show acpitool version number and release date, then exit. |
| -w | Show wakeup capable devices, these are devices capable of waking up a computer. On a laptop, LID seems enabled by default. |
| -W x | Enable/disable wakeup device x. Run 'acpitool -w' to see valid numbers for x. |
Don't blame me if acpitool can't suspend your laptop : there are quite some problematic laptops out there.
Check the acpi-bugzilla list if you don't believe me ;)
Note that some options, like -F, -l and -s, require write access to some of the /proc/acpi entries. This requires acpitool either to be run as root or either administrative measures must be taken, most likely by root, to allow ordinary users to write to these files. Creating a group for ACPI users and setting permissions accordingly comes to mind.
Also note that older laptops (< 2000) often simply don't have ACPI support, they support APM only, which may however sometimes work even better than ACPI . . .