As can be seen from the output of kill, all supported signals on the platform are shown; the first 31 of these (on your typical Linux box) are called the standard or Unix signals. Unlike the real-time signals that follow, each standard/Unix signal has a very specific name, and, as you might guess, purpose.
(Worry not; we shall discuss the real-time signals, numbers 34 to 64, in the next chapter).
The table you will see shortly, essentially reproduced from the man page on signal(7), summarizes the standard (Unix) signals in the following column order: the signal's symbolic name, integer value(s), the default action taken upon delivery to a process, and a comment describing the signal.
The default action column ...
