What ? means
It marks a question; the words supply the attitude. The same mark ends a plain request for information, a surprised double-check and a challenge; the wording tells them apart.
A rhetorical question makes a point instead of wanting an answer. It can persuade, argue or mock, and those are different things: read the wording and your relationship with the sender, not just the curl.
Is a question mark rude?
No, but it cannot make hostile wording polite. “Could you send the file?” leaves room to say no in a way “Send the file.” does not. Yet “Why haven’t you sent it?” is still shaped like a question and can land like an accusation.
What does a lone question mark mean?
Usually confusion or a prompt to answer. After something unclear, “?” asks you to explain. After an unanswered message, it nudges for a reply. Clarify the confusing part or answer the pending question rather than trading punctuation.
Standard punctuation in formal writing; repeated marks make a message more emphatic and informal.
Do not read ? alone as proof of sarcasm.
What it means when someone sends it to you
4 readingsDon't confuse it with
2Combination ideas
2Questions people ask
1Can a question mark become a wildcard?
Yes, in some systems. Converting text between character encodings (ways of storing characters) can replace unsupported characters with ?. In filename matching, that substitute may then act as a wildcard, matching any character rather than a literal question mark.
How to type ?
?\003FCodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.