I do mine in Obsidian, I just have a folder for 'computer notes' and whenever I figure out a new thing I drop it in there.
Some stuff I use often I set up as an alias too. So for example I have alias yt='yt-dlp -f "bestvideo[ext=mp4]+bestaudio[ext=m4a]/mp4"' for my most commonly used yt-dlp settings, so now I can just do yt [URL of video] to quickly download something from YouTube. Or alias rs="sudo rsync --ignore-existing -rav" for my rsync settings for a specific backup folder I copy a lot.