Obsidian is a free Markdown editor for Linux, MacOS and Windows. You can use Obsidian as note taking and Knowledge Base application. It is free for personal use and no signup required. All data are stored in your local system in plain text Markdown files. But you can sync that files with Dropbox. You can extend its feature with plugins. It supports Git versioning, Internal link, Graph view, Audio recorder, LaTeX math, Slides, Backlinks and word counts. It is still in beta stage and active development.
You can also check all available download options from here
Install Obsidian on Ubuntu
Obsidian markdown editor is available as a portable AppImage and flatpak packages. Download Obsidian in AppImage file format from the above download link and save it in your Downloads folder. open your terminal app (ctrl+alt+t) and run below commands one by one.
sudo chmod +x ~ Obsidian-0.10.11.AppImage
Here “Obsidian-0.10.11.AppImage” is the downloaded file name. You can change based on that file name.
Install Obsidian via Flatpak:
If you don’t have flatpak, then install flatpak and flathub on your Ubuntu system. Open the terminal and run below Obsidian markdown editor flatpak installation command.
flatpak install flathub md.obsidian.Obsidian
You can open Obsidian markdown editor via below command.
flatpak run md.obsidian.Obsidian