Checks I Should Have Done Before Posting

Sorry for the self-posting. I just wanted to share my post-hoc file checks since it was due-diligence I didn't think of until after I shared.

TLDR: I redirected into a file and inspected it at least enough to say I received an mkv container with an h264 video and opus audio.

Caveats

1. I am not in any way knowledgeable about security.
2. You can do weird things with some files. I have no idea if mkv, opus, or h264 have comments or chimeras. See talks by Corkami for more information.
3. Quad9 uses a dynamic TXT record to let the user know if they have configured their DNS resolver correctly, so I imagine you could receive a different file than I did. I have included a SHA-512 checksum for convenience which only tells you anything if you trust me for some reason.

Details

I ran the command from my post in a world-readable directory with >mystery_video_file substituted for | mpv -- - and inspected the download with

sudo --user=nobody -- file -- mystery_video_file

which output

mystery_video_file: Matroska data

I ran rename --last -- '' '.mkv' mystery_video_file # the '' is the empty string delimited with apostrophes and then

sudo --user=nobody -- ffprobe -hide_banner -- mystery_video_file.mkv

which output

Input #0, matroska,webm, from 'mystery_video_file.mkv': Metadata: COMPATIBLE_BRANDS: isommp42 MAJOR_BRAND : mp42 MINOR_VERSION : 0 ENCODER : Lavf60.16.100 Duration: N/A, start: -0.007000, bitrate: N/A Stream #0:0: Video: h264 (High), yuv420p(tv, bt709, progressive), 256x144 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 1k tbn (default) Metadata: HANDLER_NAME : ISO Media file produced by Google Inc. Created on: 05/29/2024. VENDOR_ID : [0][0][0][0] ENCODER : Lavc60.31.102 libx264 Stream #0:1(eng): Audio: opus, 48000 Hz, stereo, fltp (default) Metadata: HANDLER_NAME : ISO Media file produced by Google Inc. Created on: 05/29/2024. VENDOR_ID : [0][0][0][0] ENCODER : Lavc60.31.102 libopus

If you trust me and not the presenter for some inexplicable reason, the SHA-512 checksum for the video is “24345bd3ca8015c14a7d5d63d6b2a40f9d0f8c0307a65996226a496f121fa5ae934718cf58090f43ee67bc250b06804f23c73688cc871c15c1ba18d79b1a82a8”.

I just came back to comment that -- probably doesn't add security unless something like xargs which puts stdin on the command line itself is used. I have gotten in the habit of mindlessly adding it I guess.

I'd imagine you want something defined recursively like multiplication

• ( 0x = 0 )
• ( xy = x(y-1)+ x ) ( y > 0 ).

So it needs to be

• ( x^0 = c ) (c is some constant)
• ( x^y = xx^{y-1} ) (( y > 0 ) (to see why, replace multiplication with exponentiation and addition with multiplication). So what could ( c ) be? Well, the recursive exponentiation definition we want refers to ( x^0 ) in ( x^1 ). ( x^1 ) must be ( x ) by the thing we wish to capture in the formalism (multiplication repeated a single time). So the proposed formalism has ( x = x^1 = xx^0 = xc ). So ( cx = x ) hence ( c = 1 ), the multiplicative identity. Anything else would leave exponentiation to a zeroth power undefined, require a special case for a zeroth power and make the base definition that of ( x^1 ), or violate the intuition that exponentiation is repeated multiplication.

On an unrelated note, it'd be nice if Lemmy had Mathjax. I just wrote all this on mobile with that assumption, and I'm not rewriting now that I know better.

They just said :wq in school, so thanks for the tip. Hard to believe it saves even when the file hasn't been changed if you use :wq. What is the use case for that? If the file gets changed in another program and you want to revert?? Edit: Just saw the comment about the modification times being updated.

Suppose this post were true. Then it is a good post. So there exists a good post on the internet and it is not true. But this is a contradiction. So this post must be false and hence there must exist a good post on the internet

This should work with some caveats.

1. Tbis probably won't work on WSL (Linux needs direct access to your hardware).
2. For DVDs, you need to be sure libdvdcss is installed for this to work correctly

• You probably already have this on your system if you have successfully watched a dvd in Linux.

3. You may need to replace /dev/cdrom with the name of the device file corresponding to your drive.

• See https://wiki.archlinux.org/title/Optical_disc_drive#Learning_the_name_of_your_optical_drive.

4. This creates an exact copy of the disk, including the unallocated space. You would probably want to follow the guide https://wiki.archlinux.org/title/Optical_disc_drive#Creating_an_ISO_image_from_a_CD,_DVD,_or_BD

• (@BustedPancake@lemmy.world's use of mkisofs does the same thing because they copy the files on the disk rather than the whole disk. But you don't need makemkv. You should be able to use any method of copying the files and Linux should use libdvdcss to decrypt them.).

edit: caveats is note spalled caceats

edit: file → files on the disk

So amazing, but also so frustrating watching a stick figure guy get better than me in math in 15 minutes

Oh, you misunderstood my request. Instances shouldn't just allow these new dimensions if voting. The software should enforce automatic defederation with any instance that does not fully implement the new voting behavior.

😊⬆️⬅️⤴️ (hmm… maybe a parser for emoji based arrow votes)

This is exactly why I feel nervous asking questions online. I feel like a lot of the time the answer is so obvious that a bot could answer it with very little context and then I'll look silly.

I can confirm this works for the mobile website with the browser Firefox Nightly for Android (there's no reason to think it wouldn't work for other mobile browsers) too. Thanks

Ah, but where do you find the training set of all of the human-written good commit messages? 😃