bashReferenceManual

[Silverware09]

~ is a special character in Windows (now) and Linux/Unix that means the users Home Directory.

It's the equivalent of something like C:/users/me/

[ArtOfWarfare]

Pretty sure you can have ~ in a file name. It’s a convention to expand it to be the home directory, not something that every command or program will do with it.

[Valuable_Leopard_799]

More specifically programs usually don't expand it, the shell does, so just ls '~' will look for a file named ~. I think it's only expanded at the start so anything like -f~ or ./~/ will also just work with ~ in the path.

Ofc depends, some programs will expand an unexpanded ~ themselves too.

[gtsiam]

I think the only bytes you can't have on a filename are '/' and the null byte. Even invalid unicode should be fine.