"passwd" will prompt you for your existing password, and then for the new one. The new password must be typed twice. Passwords must be at least six characters long. You should be very careful when choosing a password. It should never be something that would be easily guessed such as your name, your phone number, or the name of your best friend. Choose a "word" that is not in the dictionary. People have been known to write programs to guess passwords by trying every word in the on-line dictionary. Your best bet is to take two short words, such as "blue" and "cat" and put them together to make the password bluecat. This is relatively easy to remember, yet not vulnerable to a dictionary attack. To be extra secure, throw in a random upper-case character: bluEcat. This will be next to impossible to guess. You can also use numbers and non-alphanumeric characters such as * % $ # etc. Also: