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Frequently Asked Questions


My platform supports ANSI colors, why does cli not use them?

It is probably a mistake in the ANSI support detection algorithm. Please open an issue at and do not forget to tell us the details of your platform and terminal or GUI.

How do I turn off ANSI colors and styles?

Set the NO_COLOR environment variable to a non-empty value. You can do this in your .Renviron file (use usethis::edit_r_environ()).

If you want to do this for testthat tests, then consider using the 3rd edition on testthat, which does turn off ANSI styling automatically inside test_that().

cli does not show the output before file.choose()

Try calling flush.console() to flush the console, before file.choose(). If flushing does not work and you are in RStudio, then it is probably this RStudio bug: See more details at

Why are heading separators wider than my screen in RStudio?

The display width of some Unicode characters ambiguous in the Unicode standard. Some software treats them as narrow (one column on the screen), other as wide (two columns). In some terminal emulators (for example iTerm2), you can configure the preferred behavior.

Unfortunately the box drawing characters that cli uses also have ambiguous width.

In RStudio the behavior depends on the font. In particular, Consolas, Courier and Inconsolata treats them as wide characters, so cli output will not look great with these. Some good, modern fonts that look good include Menlo, Fira Code and Source Code Pro.

If you do not want to change your font, you can also turn off Unicode output, by setting the cli.unicode option:

options(cli.unicode = FALSE)

A related issue:

Is there a suggested font to use with cli?

In modern terminals, cli output usually looks good.

If you see too wide heading separators in RStudio, then see the previous question: Why are heading separators wider than my screen in RStudio?.

If some output is garbled, then cli probably misdetected Unicode support for your terminal or font. You can try choosing a different font. In our experience output looks good with Menlo, Fira Code and Source Code Pro. Alternatively you can turn off Unicode output:

options(cli.unicode = FALSE)

If you think this is our fault, then please also file an issue at