How does the sudo key symbol work? I'm trying to write a script that requests the user password for some sudo-related commands. My goal is to emulate the default method that OS X uses to obtain the user's password, Password: followed by a key-like symbol, as seen in the screenshot attached below: 



I tried the answer from How to get a password from a shell script without echoing over on Stack Overflow that uses read -s, but that results in Password: without the key symbol when run from a script, but displays the symbol when run from the Terminal itself . What is this key symbol, and can I find it under the Characters menu?
I get the key symbol when running read -s in Terminal.

As this seems to work the same for read -s as for sudo, I assume this is a feature of Terminal (to display a key symbol whenever input is requested in silent/hidden mode).