connecting to MySQL from the command line

See here http://dev.mysql.com/doc/refman/5.0/en/connecting.html

mysql -u USERNAME -pPASSWORD -h HOSTNAMEORIP DATABASENAME 

The options above means:

-u: username
-p: password (**no space between -p and the password text**)
-h: host
last one is name of the database that you wanted to connect. 

Look into the link, it's detailed there!

As already mentioned by Rick, you can avoid passing the password as the part of the command by not passing the password like this:

mysql -u USERNAME -h HOSTNAMEORIP DATABASENAME -p

People editing this answer: PLEASE DONOT ADD A SPACE between -p and PASSWORD

Best practice would be to mysql -u root -p. Then MySQL will prompt for password after you hit enter.

After you run MySQL Shell and you have seen following:

mysql-js>

Firstly, you should:

mysql-js>\sql

Secondly:

 mysql-sql>\connect username@servername (root@localhost)

And finally:

Enter password:*********

Use the following command to get connected to your MySQL database

mysql -u USERNAME -h HOSTNAME -p