I recently asked a question about how an obfuscated program that relied on non-printable unicode characters worked.

One of the problems I had here is that when I tried copying the code into my question the unprintable characters that were needed for it to work were removed.

I know they were on my clipboard since after failing to paste them into the code editor here I was able to past them into a 3rd party online code editor where they did arrive intact.

Can my post have such invisible characters and if yes, how do I paste or add them?

  • Where were you going to copy that snippet with the unprintable chars from?
    – nicael
    Commented Dec 24, 2015 at 17:19
  • @nicael A link to the source is in the original question, but it's here. Commented Dec 24, 2015 at 18:50

2 Answers 2


We strip out non-printable characters except for TAB, CR, and LF.

I can see how this could be a problem for a few cases, but these cases are fairly rare, so I believe those questions/answers can still be posted but with non-printable characters explicitly replaced with other symbols for the sake of readability.


You're missing a question in your text, so I assume you want to paste unreadable code into the editor, but I'm curious why we'd want to support being able to paste in code that others won't be able to read?

The primary purpose of Stack Overflow is to help debug code and teach others how to avoid the bugs. Looking at the display of the editor you linked to doesn't reveal anything useful that someone could learn from; the code in question is still unreadable.

Questions asked have a life beyond the initial solving of the OPs question, they are answers to similar problems others might encounter in the future. If a question can't serve those two purposes I don't see a need for the question to exist.

To me this is a rare corner-case (ab)use of the editor that doesn't need to be addressed because it doesn't further the mission of the site. IF the problem were to significantly impact the usability of the editor for normal programming code then it'd definitely need to be addressed.

  • 2
    I think it is too early to call this off. On PPCG they post these kind of code-tricks at a daily basis so if they have this similar issue it might be worth to have a workaround or a fix.
    – rene
    Commented Dec 24, 2015 at 17:50
  • From my searching it appears that there are different capabilities for entering/displaying unicode among the various SE sites. They might have a unified editor now, but in the past it appears that wasn't so. The biggest problem is Unicode allows the creation of some very weird content, that easily is unreadable. We can deal with that using our normal editing tools and by casting votes so it might be a non-issue in the long run. Commented Dec 24, 2015 at 18:12

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