un script complet pour sauvegarder TOUTES ses bases Mysql :

!/bin/bash

nbday=$(date +"%u")
cd /chemin/backup/mysql
for i in *.sql.$nbday; do rm -f "$i"; done
mysql --user=debian-sys-maint --password="abcdef123456" -e 'show databases' | while read dbname; do mysqldump --user=debian-sys-maint --password="abcdef123456" "$dbname" > "$dbname".sql.$nbday; done