LunarCmd will launch Lunar Client from the command line.
To start with default settings run lunarcmd --version <lunar_version>. lunar_version can be any Lunar Client version (ex: 1.8.9). To use the version chooser, run lunarcmd with no arguments. You will be asked to choose a version to launch.
To build, run make. To install after building, run sudo make install. You will need to have Swift installed to build.
To download, use the appropriate zip file from Releases. Starting with LunarCmd 3.0, you will not need to have Swift installed on Linux.
You will need Python 3 and the Python modules pywebview and procbridge to sign in. When it says that you need to have the launcher open, a window should appear and then disappear after a few seconds. After it disappears, click the sign in button again and you should be able to sign in. Alternatively, you can open the Lunar Client launcher when signing in.