Password in Terminal

What's the Issue?
A lot of new users are thrown off by an inconsistency in the Ubuntu interface. When you enter a password in the GUI (graphical user interface, where you point and click), there is visual feedback—a dot or an asterisk for every character you type. When you enter your password in the terminal, the terminal doesn't seem to "accept" your password because it doesn't offer any visual feedback for the characters you enter.

How do I solve the "problem"?
Your password is being accepted in the terminal. You just aren't getting any visual feedback. Go ahead and type your password and hit Enter afterwards. If you typed your password correctly, there should be no problems.

Examples of the Inconsistency
Here is a password being typed in the GUI:

See how there are dots for each character that's entered?

Here is another example of the password being typed in the GUI:

This authentication dialogue also gives visual feedback for every character entered.

But when you enter your password in the terminal, all you see is... nothing.

Your password is still being accepted, and the command (as you can see in the screenshot) will still run.

If your password is, in fact, not being accepted, you will get an error:

So instead of seeing nothing when you enter your password and then the command executing successfully, you'll see nothing and then an error message saying

Sorry, try again

Is there something that can be done about this?
No, unfortunately. It's an inconsistency in the interface (visual feedback in the GUI, no visual feedback in the terminal), and inconsistencies confuse new users. I started a thread about this in the Ubuntu Forums called Feedback on entering password in the terminal? I even filed a bug report on the issue, but the developers have rejected it. So, you've just got to get used to it.