### Bug description

I recently finished upgrading a server to Posit Workbench 2022.07.2 Build 576.pro12, which bundled Quarto 1.1.189. In case it's relevant, immediately prior, I upgraded the OS in place from Ubuntu 16.04 -> 20.04. When I attempt to test out the Quarto rendering functionality, I get an error. 

Steps in IDE are File -> New File -> Quarto Document -> Create (HTML, knitr engine), save as "test2.qmd". _(file attached as [test2.qmd.txt](https://github.com/quarto-dev/quarto-cli/files/10290707/test2.qmd.txt) since GitHub didn't allow the .qmd extension)_

![Quarto IDE](https://user-images.githubusercontent.com/19575728/209234135-ccf0fb91-955b-4439-83fa-6384699c8328.PNG)

When I test running quarto from a simple SSH terminal, I get similar results. I also tested using a standalone install of version 1.2.280 and got the same results.

![Quarto Error](https://user-images.githubusercontent.com/19575728/209234193-864a6eb2-2fa3-4e58-a822-97ec0db05959.PNG)

Full stack trace of the error is as follows:
```
ERROR: Is a directory (os error 21)
Error: Is a directory (os error 21)
at Object.opSync (deno:core/01_core.js:172:12)
at Object.readTextFileSync (deno:runtime/js/40_read_file.js:41:17)
at readTheme (file:///usr/lib/rstudio-server/bin/quarto/bin/quarto.js:43539:21)
at readHighlightingTheme (file:///usr/lib/rstudio-server/bin/quarto/bin/quarto.js:43502:26)
at resolveTextHighlightingLayer (file:///usr/lib/rstudio-server/bin/quarto/bin/quarto.js:60313:33)
at resolveThemeLayer (file:///usr/lib/rstudio-server/bin/quarto/bin/quarto.js:60378:31)
at resolveBootstrapScss (file:///usr/lib/rstudio-server/bin/quarto/bin/quarto.js:60262:55)
at boostrapExtras (file:///usr/lib/rstudio-server/bin/quarto/bin/quarto.js:63753:25)
at themeFormatExtras (file:///usr/lib/rstudio-server/bin/quarto/bin/quarto.js:64966:16)
at Object.formatExtras (file:///usr/lib/rstudio-server/bin/quarto/bin/quarto.js:64584:96)
```

Output of Quarto Check:

![Quarto Check](https://user-images.githubusercontent.com/19575728/209234404-2696b3a6-9c5e-4cb1-b16e-ab41a1ae38d4.png)


### Checklist

- [X] Please include a minimal, fully reproducible example in a single .qmd file? Please provide the whole file rather than the snippet you believe is causing the issue.
- [X] Please [format your issue](https://quarto.org/bug-reports.html#formatting-make-githubs-markdown-work-for-us) so it is easier for us to read the bug report.
- [X] Please document the RStudio IDE version you're running (if applicable), by providing the value displayed in the "About RStudio" main menu dialog?
- [X] Please document the operating system you're running. If on Linux, please provide the specific distribution.
2022-12-22T22:17:01Z
msummersgill
bug needs-repro
closed
QMD Rendering Fails  - Error: Is a directory (os error 21)
https://github.com/quarto-dev/quarto-cli/issues/3739