A friend mentioned using control characters in passwords... like ^F and ^B, but not ^C because that's the interrupt character. Feels vaguely risky to me (does ^U empty the line? does ^W delete the last word? does your terminal emulator do some weird encoding like it does for cursor keys?) but if it works, why not?

I remember in school learning that technically speaking on Unix you could have the backspace character as part of your password too

But for the same reason with ^W and ^U I have no idea how you'd implement that in an interactive prompt without escaping

I suspect I have run into a couple bugs because of password generators putting characters that some backend system cannot process in the password. Halfwish they just did DKWhhjwqjkwqjmHSJKHAIUHQwdmlsadkl instead.