Matterhorn is a terminal client for the Mattermost chat system.

We provide pre-built binary releases for some platforms. Please see the release list to download a binary release for your platform that matches your server version:

https://github.com/matterhorn-chat/matterhorn/releases

To run Matterhorn, unpack the binary release archive and run the matterhorn binary within. Help is available via the --help or -h flag.

$ matterhorn --help
$ matterhorn

When you run Matterhorn you'll be prompted for your server URL and credentials. To connect, just paste your web client's Mattermost URL into the Server URL box and enter your credentials. See the Matterhorn User Guide on the details for providing each kind of supported credentials.

Note: Version ABBCC.X.Y matches Mattermost server version A.BB.CC. For example, if your Mattermost server version is 3.6.0 then you would download matterhorn version 30600.2.4. See Our Versioning Scheme for details.

For most of our binary releases, no additional packages need to be installed; they should just work out of the box. But here are some additional requirements that may apply for your platform:

• CentOS Steam 8
  • The ncurses-compat-libs package must be installed.

@3v1n0 maintains a Snap package here:

https://github.com/3v1n0/matterhorn-snap/ (Snapcraft page)

We provide a number of avenues for getting support:

• Frequently asked questions
• Matterhorn User Guide
• Built-in help (/help)
• Command list
• Keybinding list
• Chat with the developers on the Mattermost Community server
• File tickets on this repository

• Channel creation, deletion, and membership management commands
• Support for multiple teams
• Optimized channel-switching modes: M-a, M-s, and C-g
• Message posting, editing, replying, and deletion
• Markdown rendering
• Support for participating in threads via the thread window
• Convenient URL-opening with local browser
• Secure password entry via external command (e.g. OSX keychain)
• Secure authentication token entry via external command (e.g. OSX keychain)
• Yank verbatim content from messages into the system clipboard
• Optional live preview during message editing
• Optional smart quoting for efficient Markdown entry
• Edit messages with $EDITOR
• Rebindable keys (see /help keybindings)
• Message editor with kill/yank buffer and readline-style keybindings
• Support for adding and removing emoji post reactions
• Support for channel muting
• Tab-completion of:
  • Usernames: type @, then Tab to cycle through matches
  • Channel names: type ~, then Tab to cycle through matches
  • Commands: type /, then Tab to cycle through matches
  • Emoji: type : and then some text, then Tab to display and cycle through matches
  • Fenced code block languages: type three backticks to begin typing a code block, then Tab to cycle through available languages
• Support for attachment upload and download
• Spell-checking via Aspell
• Syntax highlighting of fenced code blocks in messages (works best in 256-color terminals)
• Flagging and unflagging of posts, which are then viewable with M-8 or /flags
• Support for SOCKS 4 and 5 proxies via the ALL_PROXY and HTTPS_PROXY environment variables. (Plain HTTP proxies are not yet supported.) Also supports NO_PROXY.
• Multiple color themes with color theme customization support
• Custom notifications via notification scripts (see the activityNotifyCommand configuration setting and docs/notification-scripts.md for details).
• Optional mouse support

Matterhorn version strings will be of the form ABBCC.X.Y where ABBCC corresponds to the lowest Mattermost server version expected to be supported by the release. For example, if a release supports Mattermost server version 1.2.3, the ABBCC portion of the matterhorn version will be 10203. There may be later versions of the Mattermost server that are supported (e.g. Matterhorn 50200.X.Y supports Mattermost server versions 5.2 through at least 5.8).

The X.Y portion of the version corresponds to our own version namespace for the package. If the server version changes, X.Y SHOULD be 0.0. Otherwise the first component should increment if the package undergoes major code changes or functionality changes. The second component alone should change only if the package undergoes security fixes or other bug fixes.

Overall, we strive to build a terminal client that provides the same basic feature set as the web client. This is reflected in the state of the client, our issue backlog, and the content of our wiki feature design discussions.

We intend to add web client features to Matterhorn to the extent that they can be added sensibly in a terminal setting. Our goal is to do so in a way that minimizes surprise to web client users migrating to Matterhorn while also providing the best terminal user experience that we can think of. That might entail adding the web client features but changing their designs to ones better suited for terminal use or it might mean omitting aspects of web client features that rely heavily on mouse- or DOM-related UI idioms. It might also entail adding web client features but deviating slightly on specific behaviors.

If you are used to a web client feature and don't see it in Matterhorn, that's probably because we just haven't gotten to it yet. We would be happy to hear from people wanting to contribute! If you can't contribute, search existing issues to see if we already have an issue for it, or create a new issue and let us know!

If you decide to contribute, that's great! Here are some guidelines you should consider to make submitting patches easier for all concerned:

• If you are new to Haskell and are unsure how much Haskell you need to know in order to contribute, please see our list of Haskell skills needed.
• Please base all patches against the develop branch unless you are specifically fixing a bug in a released version, in which case master is a fine place to start. Please also do this for submodules that have a develop branch if you need to contribute changes to submodules.
• If you want to take on big things, let's have a design/vision discussion before you start coding. Create a GitHub issue and we can use that as the place to hash things out. We'll be interested to discuss any usability / UI, performance, or compatibility issues.
• Please make changes consistent with the conventions already used in the codebase.
• We follow a few development practices to support our project and it helps when contributors are aware of these. Please see our practices document for more information.

If you just want to run Matterhorn, we strongly suggest running a binary release (see above). Building from source is only recommended if you intend to contribute.

If you want to contribute changes to Matterhorn, you'll need to build it from source. See our building instructions for details.