MySQLTuner is a Perl script that can help you tune your MySQL server. We
all know the MySQL variables can be a bit hard to read, and it's even
harder to get useful data out of it and optimize your server with it.
That's where MySQLTuner can lend a hand. It displays statistics and recommendations about your MySQL installation, thus revealing the areas where your configuration might be optimized. Though it's a useful tool, it's hardly the answer to bad performing MySQL servers. In such a case, the only remedy is getting your hands dirty. Review and optimize queries, check your application's programming and so forth.
On a Debian based machine, you can simply type in:
sudo apt-get install mysqltuner
Otherwise you should just download the script and make it executable:
chmod +x mysqltuner.pl
When you download it, you have to run the script instead of entering the command: