On seeing just the title, before reading the article, I assumed it was about the Wingdings J.

Seemed to be a common occurrence from Microsoft Outlook users.

I remember discovering this in about 2010, and thought it was hilarious

A stray &quot;J&quot; I encountered years ago: a certain client&#x27;s support tickets would often end with a single &quot;J&quot;, which was a little confusing as it was not one of their name initials. After a brief investigation, the original email source contained this:<pre><code> &lt;font face=&quot;Wingdings&quot;&gt;J&lt;&#x2F;font&gt;
</code></pre>
Which renders as a smiley face.

If it&#x27;s any consolation, the other day I spent 3 hours diagnosing a homebrew circuit board for no signal and finally realized the Raspberry Pi sending the signal had a dead GPIO pin.

&gt; \n is ^J (ctrl-J) so there&#x27;s some logic thereThe same &#x27;j&#x27; as vi uses for &#x27;hjkl&#x27;.
<a href="https:&#x2F;&#x2F;vi.stackexchange.com&#x2F;questions&#x2F;42426&#x2F;why-did-vi-use-hjkl-instead-of-jikl&#x2F;42428#42428" rel="nofollow">https:&#x2F;&#x2F;vi.stackexchange.com&#x2F;questions&#x2F;42426&#x2F;why-did-vi-use-...</a>

Some tool or library is interpreting the newline as two characters (as you note), and then a subsequent step is removing unprintable characters. Things like this used to frequently happen in shells, Perl, PHP, and so on.

&gt; \n is ^J (ctrl-J) so there&#x27;s some logic thereSpecifically, J is the 10th letter of the alphabet and therefore ctrl-J is code for ascii 10. Same reason ctrl-D sends EOF and ctrl-I sends tab.

\n is ^J (ctrl-J) so there&#x27;s some logic there, but I wonder if something has been lost in the message. I&#x27;d guess it either displays ^J or an inverse-colour J, rather than just a plain lowercase j.Also possible that the j is a red herring and just some random character that&#x27;s always there. Pasting a URL containing a newline into most browsers just truncates it at the newline, regardless of how much text is after. I only know this from occasionally copying links from a terminal window where the copy somehow added newlines every 80 characters (even though copying this way normally works fine). I&#x27;d have to copy the URL with newlines into a text editor, remove the new lines and copy again to be able to paste it.

This comes up fairly often in TeX, where you can use ^^J to insert a newline character [0]. For example, the following code:<pre><code> \message{before ^^J after}
</code></pre>
prints the following message:<pre><code> before 
 after
</code></pre>
This is common in other old software too [1] [2], but TeX is where I see it the most often these days.[0]: <a href="https:&#x2F;&#x2F;tex.stackexchange.com&#x2F;a&#x2F;64848&#x2F;270600" rel="nofollow">https:&#x2F;&#x2F;tex.stackexchange.com&#x2F;a&#x2F;64848&#x2F;270600</a>[1]: <a href="https:&#x2F;&#x2F;superuser.com&#x2F;q&#x2F;212874" rel="nofollow">https:&#x2F;&#x2F;superuser.com&#x2F;q&#x2F;212874</a>[2]: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Caret_notation" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Caret_notation</a>

I thought it was a strange way to express the problem, too. OP didn&#x27;t really explain where or how the clipboard text was getting pasted in order to reproduce the issue.

Yeah, I don&#x27;t understand this. What broken tool is turning newlines into j?

the ANSI escape sequences for screen erasing start with ESC and end in J. When you display a string on a screen including a newline at the end of it, you need to erase to the end of the line on the screen so you don&#x27;t leave predecessor garbage which would be confusing.That&#x27;s how the J got inserted, then whatever is processing this is swallowing the rest of the escape sequence but leaving the J. The fix is there, take the J with the rest of the escape sequence at whatever layer is doing this.<pre><code> ESC[J erase in display (same as ESC[0J)
 ESC[0J erase from cursor until end of screen
 ESC[1J erase from cursor to beginning of screen
 ESC[2J erase entire screen
 ESC[3J erase saved lines
</code></pre>
ASCII and then ANSI were invented as in-band communications and terminal control protocols, not &quot;file formats&quot;. You thread filters together like beads on a string, where ASCII is somebody&#x27;s job, and ANSI is somebody&#x27;s job, and then the rendered text is presented to the user.unix is ingenious how it has accomodated changes and conflicting ideas, incorporating the new squoze next to the old, like UTF-8 because the same people did that. It&#x27;s not perfect, but it proved &quot;worse is better&quot; because it for a long time it outcompeted its alternatives and never became bloated and overburdened by bureaucratic committee ideas.however today&#x27;s developers did not &quot;come up&quot; in the same culture of apprenticeship learning so a lot of the clever subtlety has been lost and now worse is starting to be worse, and guess what, there is no better.

&gt; but in ANSI newline delimiter is translated as &quot;j&quot;?

<a href="https:&#x2F;&#x2F;zippythepinhead.com&#x2F;Merchant2&#x2F;merchant.mv?Screen=PROD&amp;Product_Code=28-Sept-98&amp;Category_Code=s1998&amp;Product_Count=23" rel="nofollow">https:&#x2F;&#x2F;zippythepinhead.com&#x2F;Merchant2&#x2F;merchant.mv?Screen=PRO...</a>

As a vim user, stray J&#x27;s are a fact of life.

I can’t tell if this is sarcasm or not. I chuckled either way.

Impossible, Signal TUI is written in Rust.

So this is a bug in that Signal TUI he was using? I.e. it mangles newlines in pasted text.

IIRC you don’t even need the -r flag since -j incorporates its behavior (minus newlines).

Today I learned that jq -Rrj is a shorter command line for doing the same as tr -d &#x27;\n&#x27;.

I like how -j fixed the stray j problem....

I was poking around with this and I noticed wl-copy has an option to trim newlines. Maybe that&#x27;s why they added the option but I&#x27;m leaning towards gurk being the culprit. wl-copy itself seems to handle newlines ok, at least for me. This works as expected:<pre><code> echo -e &quot;test\n&quot; | wl-copy

 wl-paste</code></pre>

A stray "j" ruined my evening