Sometimes, shit happens. If you’re reading this, it probably just happened. Either you forgot your password or somehow you set it to something else through a script, or something else equally terrible happened. Regardless, you need to reset your password. First, you should probably make a backup of your data in case something goes horribly wrong. This should work on almost any version of Ubuntu (or other versions of Linux), but it is tested on Ubuntu 10.04 with mysql-server 5.1.
First, we need to shut down MySQL. This is going to bring all your database-driven sites down (though caching may save you). Then we will restart it, while ignoring the permissions table.
sudo stop mysql sudo mysqld --skip-grant-tables & # Note the PID that is printed out, such as "[1] 14053", where "14053" is the PID.
Now we log in with no password, and reset the password.
mysql -u root
UPDATE user SET Password=PASSWORD('YOURNEWPASSWORD') WHERE User='root'; FLUSH PRIVILEGES; exit;
The password is reset! Now we need to kill off the passwordless instance, and restart a normal MySQL server.
# PID is the number from before, probably 4 or 5 digits sudo kill PID sudo start mysql
Now make sure you can log in!
mysql -u root -p YOURNEWPASSWORD
