I discovered that it's possible to use "icon" in terminal (for eg in prompt) on OS X, as it can be seen here:
Is it possible to do this on a regular Linux distribution (eg ubuntu) ?
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These are unicode symbols or emoji. Homebrew used to have a Beer Mug as a symbol in its output. As long as you have a font that supports them you will see them. On macOS you can go to the Edit > Emoji and Symbols... to insert them. Not sure of the equivalent on Ubuntu. You should be able to copy-and-paste them into your text editor from here.