sysvorOrt /var/log/mysql # mysql -h localhost -u michi -pmysql: [ERROR] unknown variable ‚log-error=/var/log/mysql/error.log‘.

# /etc/mysql/my.cnf: The global mysql configuration file.

!includedir /etc/mysql/mysql.d
[client]
port		= 3306
socket		= /var/run/mysqld/mysqld.sock
[mysqld]
#
# * Basic Settings
#
# Ab Version 5.1 können Sie das Protokoll zur Laufzeit aktivieren!
general_log = 1
general_log_file = /var/log/mysql/mysql.log
		
pid-file	= /var/run/mysqld/mysqld.pid
socket		= /var/run/mysqld/mysqld.sock
port		= 3306
basedir		= /usr
datadir		= /var/lib/mysql
tmpdir		= /tmp
lc-messages-dir	= /usr/share/mysql
[client]
user=michi
password=xxxxxxxxxxxx
#
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
bind-address		= 127.0.0.1
#
#
#
log-error = /var/log/mysql/error.log
#

Hier muss überprüft werden ob die Datei /var/log/mysql/error.log Rechte hat. Also ab Besten ein

#chmod 777 /var/log/mysql/error.log eingeben

Ggf den ganzen Ordner freigegeben.
Es kann getestet werden in der Konfigurationsdatei general-log-file = /var/log/mysql/mysql.log (also Bindestriche statt Unterstriche) zu verwenden.