How to create a listener for a forked process?

Question

I want to create a pair of bash functions something along the lines of

function generator {
    while [ 1 -le 1 ]
    do
        # run log generator > somefile.log
    done
}

function tail_log {
    generator &
    tail -f somefile.log
}

So, I would run the command tail_log to see the log output. Except, instead of the infinite loop, I'd like allow the user to press Q to terminate the forked process.

So it looks like I need two things:

1. a way to get the process ID of a forked prcoess
2. a way to listen for user input so I can kill the process ID when the user presses Q

Answer 1

1. $!

2. Run tail in background as well. In foreground, use the read builtin. On input, kill both background processes.

   While I'm at it:

3. while [ 1 -le 1 ] → while true (see somewhat related section on BashPitfalls)

4. function foo {...} → foo() {...} (see deprecated syntax about this)