Again, I'm not sure what 'kill -- -$$' is even trying to do. -- is not a valid option for kill, and killing your own shell would kill everything, leaving it not able to do anything. And -(number) would tell kill it's some strange kind of signal, not a process ID.

This is different from our suggestions how? Wait up to 5 seconds then kill, and if it had to be killed, email?

Once again, this logic doesn't make sense. & on a line by itself is meaningless, and -- why bother making a second subshell? You already have two shells, and you never background the second one anyway.

Oh, I see -- you are trying to launch two scripts simultaneously. Each will kill the other if it finishes first.

This doesn't seem a good way to solve the problem, really. That's the very definition of "race condition". Even assuming good conditions, who can say whether one will kill the other in time? Who can say whether they will die cleanly?

And there's no point! It's an over-complicated, extra-wasteful, extra-sloppy, extra-error-prone version of the exact same algorithm: "Wait up to x seconds, then kill and send email".

If you're trying to avoid some sort of problem with this convoluted method, it'd be nice to know what problem, so that we can show you how to actually avoid it.

I don't know what you're even trying to say here.

I will make my solution more complete in the hope you will actually try it:

Code:

#!/bin/bash

(
        echo "Hi!"

        # Using 'exec' means less mess if something goes wrong,
        # since the subshell is replaced wholly by it.
        exec sleep 1000
# Less stderr noise if you use 'disown'.
# If your shell doesn't have disown, it doesn't need it.
) & disown

PID="$!"        # The PID of the background process

MAXTIME=5
X=0 ; while [ "$X" -lt "$MAXTIME" ]
do
        let X=X+1
        # If the process is done, quit immediately
        ps "$PID" 2>&1 >/dev/null || exit

        echo "$X seconds, $PID still exists" >&2
        sleep 1
done

# The query hasn't finished in 5 seconds, so kill it.
kill "$PID" >/dev/null 2>&1 || exit

ERECIPIENT3="email.com"
# echo "Connection on status: is Down"|mail -s "Subject:" "${ERECIPIENT3}" >/dev/null 2>/dev/null

sleep 1 # Wait a second for it to die

# Kill it with a more severe signal and exit if it doesn't exist
kill -QUIT "$PID" >/dev/null 2>&1 || exit
sleep 1
# Try and kill it again with an unblockable signal, quit if it doesn't exist
kill -9 "$PID" # Last resort
exit

If 'mail' is hanging, it might be a good idea to find out why.