When apcupsd detects anomalies from your UPS device, it will make some decisions that usually result in one or more calls to the script located in /etc/apcupsd/apccontrol. The apccontrol file is a shell script that acts on the first argument that apcupsd passes to it. These actions are set up by default to sane behaviour for all possible situations apcupsd is likely to detect from the UPS. Nevertheless you can change the apccontrol behaviour for every single action. To do so create a file with the same name as the action, which is passed as a command line argument. Put your script in the /etc/apcupsd directory.
These events are sent to the system log, optionally sent to the temporary events file (/etc/apcupsd/apcupsd.events), and they also generate a call to /etc/apcupsd/apccontrol which in turn will call any scripts you have placed in the /etc/apcupsd directory.
Normally, /etc/apcupsd/acpcontrol is called only by apcupsd. Consequently, you should not invoke it directly. However, it is important to understand how it functions, and in some cases, you may want to change the messages that it prints using wall. We recommend that you do so by writing your own script to be invoked by apccontrol rather than by modifying apccontrol directly.
In other case, you may want to write your own shell scripts that will be invoked by apccontrol. For example, when a power fail occurs, you may want to send an email message to root. At present the arguments that apccontrol recognizes are:
apccontrol accepts the following command line options:
To write your own routine for the powerout action, you create shell script named powerout and put it in the lib directory (normally /etc/apcupsd). When the powerout action is invoked by apcupsd, apccontrol will first give control to your script. If you want apccontrol to continue with the default action, simply exit your script with an exit status of zero. If you do not want apccontrol to continue with the default action, your script should exit with the special exit code of 99. However, in this case, please be aware that you must ensure proper shutdown of your machine if necessary.
Some sample scripts (onbattery and mainsback) that email power failure messages are available in the examples directory of the source code.