To edit a file, first make a back-up.
cp /etc/my.cnf /etc/my.cnf.old
Now open it in nano:
nano /etc/my.cnf
Use the arrows to navigate around. Or:
CTRL-W brings up a search box, type in the value you are looking for and hit enter.
CTRL-V is page down
CTRL-Y is page up
CTRL-K deletes the line the cursor is on
CTRL-X to exit... if you want to save the changes you have made, hit Y. If you don't want to save your changes (like if you made a dastardly mistake, which I do often) hit N. You can always go back into nano again and re-try at making the changes correctly.
Once you are done,
Restart MYSQL:
/etc/init.d/mysql restart
Your changes will now take effect.
