Prompt overwrites last displayed line when catting file without trailing newline

[woutgg]

When using cat to display a file without trailing newline, the last line can (sometimes) be seen very briefly and is then overwritten by the (left-)prompt.

Perhaps a non-empty line could be detected in which case the prompt either does not clear the line, or emits a newline first.

[agkozak]

Have you tried setting

AGKOZAK_BLANK_LINES=1

in your .zshrc? That's a simple solution.

[woutgg]

Ah, I missed that one. It's not exactly what I had in mind but it might work just fine; I'll try it for a while. Thank you!

[edemaine]

I'd personally prefer not to add a blank line every time, only when necessary (with some kind of "(no EOL)" marker). But I'm not sure it's possible to detect beginning-of-line — is it?

Maybe it is: https://stackoverflow.com/questions/8343250/how-can-i-get-position-of-cursor-in-terminal

[woutgg]

That would be my preference as well.
I thought at first that it would be possible to detect/request cursor position, but on second thought I'm not sure if it's feasible to do so in the context of a shell prompt (as far as I know you'd have to read 'keyboard input' emitted by an ANSI command). I'm far from an expert at this though.

[agkozak]

@woutgg @edemaine Could you try adding

setopt PROMPT_CR

to the end of your .zshrc and see if that produces the desired effect?

[woutgg]

That works very nicely, especially since it highlights the fact that the output is unterminated.
I wasn't aware of this option. Interestingly it appears to be on by default, so it is probably switched off somewhere in a plugin.
Thank you!

[agkozak]

Interestingly it appears to be on by default, so it is probably switched off somewhere in a plugin.

@woutgg You're absolutely right, and it's my fault that it's getting turned off. I'll get this fixed in the next couple of days, all right? Thanks for your patience, and thanks for giving that temporary fix a try.

[agkozak]

Release v3.11.4 contains a fix for the reported behavior. Just go ahead and update the master branch, and thanks, everyone, for helping to make the prompt better.

[edemaine]

Awesome, thanks both for finding the option and fixing it!

For anyone running into this, I also found it nice to be able to customize the string (default is % in standout font, or equivalently %S%%%s):

export PROMPT_EOL_MARK="%S[NO EOL]%s"

Sadly it doesn't seem to be possible to put this on the line after the unterminated line (as far as I can tell). Oh well, good enough!

[woutgg]

Great, thank you @agkozak for your efforts on this and the awesome prompt in general!

[AndydeCleyre]

Just popping in with another fun EOL mark:

PROMPT_EOL_MARK='%F{red} %f'