As Chealion mentioned, there are several ways that your mysql could have been installed. Each of which will place your data dir and/or logs in different locations. The following command will give you (and us) a good indication of where to look.
ps auxww|grep [m]ysqld
# Putting brackets around the first char is a `grep`+`ps` trick
# to keep it from matching its own process.
# Note: For zsh compatibility put quotes around the grep regex
Can you post the result of that command here please? Mine looks like this:
_mysql 101 0.0 0.3 112104 13268 ?? S 12:30AM 0:13.20 /opt/local/libexec/mysqld --basedir=/opt/local --datadir=/opt/local/var/db/mysql --user=mysql --pid-file=/opt/local/var/db/mysql/rbronosky-mbp.pid
root 76 0.0 0.0 600172 688 ?? S 12:30AM 0:00.02 /bin/sh /opt/local/lib/mysql/bin/mysqld_safe --datadir=/opt/local/var/db/mysql --pid-file=/opt/local/var/db/mysql/rbronosky-mbp.pid
From that you can see that my datadir is /opt/local/var/db/mysql (because I installed via MacPorts). Let’s take this lesson a bit further…
From the first line you can see the my daemon is /opt/local/libexec/mysqld. The mysqld can be called with --verbose --help to get a list of all command line options (and here is the important/valuable part!) followed by the values that would be used if you were launching mysqld instead of just checking the help output. The values are the result of your compile time configuration, my.cnf file, and any command line options. I can exploit this feature to find out EXACTLY where my log files are, like so:
/opt/local/libexec/mysqld --verbose --help|grep '^log'
Mine looks like this:
log /tmp/mysql.log
log-bin /tmp/mysql-bin
log-bin-index (No default value)
log-bin-trust-function-creators FALSE
log-bin-trust-routine-creators FALSE
log-error /tmp/mysql.error.log
log-isam myisam.log
log-queries-not-using-indexes FALSE
log-short-format FALSE
log-slave-updates FALSE
log-slow-admin-statements FALSE
log-slow-queries (No default value)
log-tc tc.log
log-tc-size 24576
log-update (No default value)
log-warnings 1
LO AND BEHOLD! all of the advice in the world was not going to help me because my log file is kept in a completely non-standard location! I keep mine in /tmp/ because on my laptop, I don’t care (actually I prefer) to loose all of my logs on reboot.
Let’s put it all together and make you a oneliner:
$(ps auxww|sed -n '/sed -n/d;/mysqld /{s/.* \([^ ]*mysqld\) .*/\1/;p;}') --verbose --help|grep '^log'
Execute that one command and you will get a list of all of the logs for your running instance of mysql.
Enjoy!
This Bash-Fu brought to you for free by my commitment to all things Open Source.