Hemingway Editor is not available for Linux but there are plenty of alternatives that runs on Linux with similar functionality. The best Linux alternative is Joplin, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 100 alternatives to Hemingway Editor and many of them are available for Linux so hopefully you can find a suitable replacement. Other interesting Linux alternatives to Hemingway Editor are Zettlr (Free, Open Source), Manuskript (Free, Open Source), Dendron (Free, Open Source) and bibisco (Freemium, Open Source).
Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, can be copied, tagged and modified either from the applications directly or from your own text editor.
Zettlr is a supercharged markdown editor that combines many writing editor features and collect them in one application. It aims at speeding up your workflow and help you write without any interruptions.
Manuskript is an open-source tool for writers, with outliner, character management, plot development, distraction-free editor, etc. Outliner Organize your thoughts and snippets in a hierarchical manner. Organize them as you wish, reorganize them on the go.
Dendron is an open-source, local-first, markdown-based, note-taking tool built on top of VSCode. It supports all the usual features you would expect like tagging, backlinks, a graph view, split panes, and so forth.
yWriter is a writing tool that uses "scenes" as a unit of text and allows you to associate that text with all manner of story elements (characters, locations, items) as well as place it and rearrange it within the context of chapters.