# list available targets
#
update-alternatives --list my.cnf

# show further information including current selection, best selection and  priority, where 
# a higher value has priority (automatic selection)
#
update-alternatives --display my.cnf 


# To select a specific implementation, use the following command as root and then select
#  a number from the list:
#
# also useful to see the current selection
#
update-alternatives --config my.cnf


# Return to automatic selection
#
update-alternatives --auto my.cnf


# delete an alternative
#
#     update-alternatives --remove my.cnf <Pfad>
#
update-alternatives --remove my.cnf /usr/local/mysql/etc/my.cnf