Show privileges for all users in MySQL

Example script:

mysql   --silent \
        --skip-column-names \
        --user mysqldumper \
        --execute 'SELECT User, Host from mysql.user' | \
        while read User Host; do 
            mysql --user mysqldumper --execute "SHOW GRANTS FOR '$User'@'$Host'"; 
            echo "==========================="; 
        done

The mysqldumper user only requires read permissions on the databases.