detect shutdown state from bash script

[ThatDude]

Hi

 

I have a bash script that starts with the array and continues running in a while loop.

 

This script is preventing my server from shutting down (if I kill the script manually shutdown works as expected).

 

What's the most efficient way to detect a shutdown state from within the bash script so I can have it self terminate?

 

Something like:

 

if exists /tmp/shutdown.txt; then exit 1; fi 

 

Many thanks

Edited January 21, 2023 by ThatDude
more info

[apandey]

2 hours ago, ThatDude said:

What's the most efficient way to detect a shutdown state from within the bash script so I can have it self terminate?

You should trap SIGTERM and terminate when you see it. How you do it is up to you - set a poison pill variable or kill $$

 

EDIT: SIGTERM is sent to process initially on shutdown, but a SIGKILL is also sent subsequently. So just make your script handle the signals properly

Edited January 22, 2023 by apandey

[ThatDude]

10 hours ago, apandey said:

You should trap SIGTERM and terminate when you see it. How you do it is up to you - set a poison pill variable or kill $$

 

EDIT: SIGTERM is sent to process initially on shutdown, but a SIGKILL is also sent subsequently. So just make your script handle the signals properly

 

Thank you.

 

SIGINT was the missing part of the puzzle, I've never come across that before.

 

#!/bin/bash
exit_script() {
    trap - SIGINT SIGTERM # clear the trap
    kill -- -$$ # Sends SIGTERM to child/sub processes
}

trap exit_script SIGINT SIGTERM

while true; do
    echo "Do some task"
done