What does this letter mean?

The program reads data from the standard input.

This input device is very easy to use.

Learning a new input method is difficult.

His voice is husky and very attractive.

I bought a new acrylic key holder.

Using hotkeys can increase work efficiency.

In this software, you can streamline your work using shortcut keys.

Let's set the keyframe for this animation.

I can't find my keycard, so I can't get into the room.