Is there a way to hide info and warning messages on marp-cli?

[j2deme]

I'm working on custom Python script to manage my markdown slides, this script includes exporting single slides with Marp, in which case it shows the corresponding info and warning messages, and I don't have any problem with this behavior on this specific section.

My problem is that I also implemented a batch exporting, and decided to include a progress bar to show... well the progress, but as the info and warning messages appear they conflict with the progress bar and make it reappear instead of being updated as a single bar.

I hope I have explained myself, anyway, I guess an image is better than thousand words.

If there was a way to hide those messages, I think my interface could behave as expected.

The current line that I'm calling in this section of my script is the following:

os.system(f"marp {SOURCE_DIR}/{slide}.md --output {DIST_DIR}/{slide}.pdf --allow-local-files --pdf-outlines --pdf-outlines.pages=false --pdf-notes")

I know there is also an option to user --input-dir and --output, but if I use that syntax I get even more messages about missing CSS files (which are not missing).

Thanks in advanced.

[yhatt]

You can simply suppress the Marp CLI logs that are being output to stderr. Example in the shell:

marp foobar.md 2>/dev/null

I'm not familiar with Python, so providing a clear solution for your use case is difficult for me.

[j2deme]

My bad, I forgot to specify that I'm working on Windows.

Now that you mentioned it, it's true, I can use /dev/null on Unix based systems, anyway, it was just a matter of finding the alternative for /dev/null on Windows and I found that you can use > NUL 2>&1 at the end of a command line program and it pipes stderr and stdout to null.

I finally got the expected result 😄

Thanks for tip!

[yhatt]

If you are trying to spawn the CLI programatically, using the language feature to suppress stderr might be a smarter way.

Specifically, you can use the subprocess module and set the stderr option to DEVNULL to execute the command. It should be a consitent result in different OS.

import subprocess

subprocess.run(["marp foobar.md"], stderr = subprocess.DEVNULL)

I am not experienced in Python, so please note that I cannot guarantee the correctness of this answer.