Piping the output of rich print to a file introduces unwanted newlines if the line is longer than what fits on the screen

[katrinm86]

So my colleague recently noticed that the output of the print function includes multiple lines if it gets piped to a file e.g.

./myscript.py > test.txt; cat test.txt | wc -l

would produce 2 as there are really two lines in the file ...

If we remove the import from rich import print it reverts back to a single line.

Is this something that can be configured? Or is it a bug? There are (correctly) no color control characters so that seems to work fine ...

[MaxFreedomPollard]

This is rich falling back to a default width when it can't see a real terminal. When you pipe or redirect, sys.stdout isn't a TTY, so the Console can't detect the width, defaults to 80 columns, and word-wraps anything longer, writing real newlines into the file.

Quick confirmation of what's happening (rich 15.0.0):

from rich.console import Console
c = Console()
print(c.is_terminal, c.width)   # to a file this prints: False 80
c.print("X" * 200)              # gets split into 80 + 80 + 40 with newlines

Three ways to stop it, pick whichever fits:

1. Use a Console and pass soft_wrap=True. This is the "print what I gave you, don't wrap or crop" switch:

from rich.console import Console
console = Console()
console.print("X" * 200, soft_wrap=True)   # stays a single 200-char line in the file

Note the module-level rich.print() doesn't take soft_wrap (its only kwargs are sep, end, file, flush), so you need a Console instance for this one.

2. Give the Console an explicit wide width so it never wraps:

Console(width=10_000).print("X" * 200)

3. Set the COLUMNS environment variable, which rich honors even when the output isn't a terminal:

COLUMNS=500 python yourscript.py > out.txt

I'd reach for soft_wrap=True if you just want the file to hold exactly the lines you printed and let your pager or editor wrap them. Use option 2 or 3 if you actually want wrapping, just at a wider column than 80. All three keep your styles and markup intact; soft_wrap only turns off rich's own wrapping and cropping.

Verified on rich 15.0.0: redirected to a file, the default emits the 200-char line as 80/80/40, and both soft_wrap=True and a wide width keep it as one 200-char line.

[katrinm86]

Thank you very much for the fast answer!

I'm probably going with not using "from rich import print" and using it only explicitly via Console.

Just as a note: I think its a bit counterintuitive to break with user expectations there e.g. I would never expect the standard "print" to insert line breaks when using pipes :/