Signal transmission between script and application under linux

As the title:
The knowledge to be learned is as follows:

The use of the kill command in the script under linux:

Writing elegant shell scripts (four)-reasonable use of the kill command

The Linux script and program's processing scheme for SIGINT, the script transmits signals to the program through kill

Find the pid of a specific program in the script

Linux shell obtains pid
shell study notes according to the process name
(3) What does grep -v grep|awk'{print $2}' `mean

Signal function operation

In addition, because you need to process the signals sent by these scripts in the application, you need to know the relevant operations of the program on the signal under linux:
Linux signal two signal processing function registration