Prompt to backup DBs over 100mb -- if timeout default to backup

vagrant_halt_custom.sh

#!/bin/bash
#
# Create individual SQL files for each database automatically, 
# but give me a chance to skip it. These files
# are imported automatically during an initial provision if
# the databases exist per the import-sql.sh process.
echo 'Starting custom vagrant halt...';
mysql -e 'show databases' | \
grep -v -F "information_schema" | \
grep -v -F "performance_schema" | \
grep -v -F "mysql" | \
grep -v -F "test" | \
grep -v -F "Database" | \
while read dbname; do
        db_size=$(mysql -uroot -ss -N -e "SELECT COALESCE(ROUND(SUM(data_length + index_length) / 1024 / 1024),0) AS 'size' FROM information_schema.TABLES WHERE table_schema = '$dbname'");
        if [ 100 -lt $db_size ]; then
                while [ -z "$answer" ]; do
                        read -t 10 -p "$dbname seems large, back it up now? " answer </dev/tty
                        case "$answer" in
                           [yY]* ) answer='';
                                   mysqldump -uroot "$dbname" > /srv/database/backups/"$dbname".sql
                                   echo "Database $dbname backed up..."
                                   break;;
                           [nN]* ) answer=''
                                   break;;
                           '')     answer='';
                                   mysqldump -uroot "$dbname" > /srv/database/backups/"$dbname".sql
                                   echo "Database $dbname backed up..."
                                   break;;
                           * )     answer=''
                                   echo "Dude, just enter Y or N, please."
                                   continue;;
                        esac
                done
        else
                mysqldump -uroot "$dbname" > /srv/database/backups/"$dbname".sql && echo "Database $dbname backed up...";
        fi
done;