mysql log files are empty although it seems that I have set eveything

I am trying to get log files for mysql server Ver 14.14 Distrib 5.5.22 running on debian-linux-gnu (x86_64) using readline 6.2

Based on several websites I uncommented these lines in /etc/mysql/my.cnf:

general_log_file        = /var/log/mysql/mysql.log 
general_log             = 1

After running mysql I checked that /var/log/mysql/mysql.log was not created. A website suggested to run two commands:

touch /var/log/mysql/mysql.log
chown mysql:mysql /var/log/mysql/mysql.log

This did not help: still no logs! The file is empty.