#!/bin/bash

recordings=0

update() {
    if [ "$recordings" -gt 0 ]; then
        echo " Recording"
    else
        echo
    fi
}

begin_record() {
    recordings=$((recordings + 1))
    update
}

end_record() {
    recordings=$((recordings - 1))
    update
}

exec sleep infinity &

pid="$!"
trap begin_record SIGUSR1
trap end_record SIGUSR2
trap "kill $pid" EXIT

while :; do
    wait "$pid"
done