This one is for lazy ones! If you are paranoid about security, do not use this.
~/.my.cnf and add following lines in it and replace mysqluser & mysqlpass values.
[client] user=mysqluser password=mysqlpass
For safety, make this file readable to you only by running
chmod 0600 ~/.my.cnf
Next time you run mysql commands mysql, mysqlcheck, mysqdump, etc; they will pick username & password from this file if you do not provide them as argument (-u and -p). It can save your time.
Of-course, if you specify username and password explicitly as part of commands arguments, they will be used.