To build this software on Ubuntu and Debian systems just run make.
Other systems might not be supported. If you manage to compile capsled on other distros please update capsled.c and the Makefile and submit a pull request.
This software needs to be run as root/with root privileges for reading the capslock keystrokes and controlling the power led.
Running make install (as root) installs the software to usr/bin/ and creates and enables it's service in /etc/systemd/system/