signal-cli is a command-line interface for libsignal-service-java. It supports
registering, verifying, sending and receiving messages. To be able to link to
an existing Signal-Android/signal-cli instance, signal-cli uses a patched
libsignal-service-java, because libsignal-service-java does not yet support
provisioning as a slave device. For registering you need a phone number where
you can receive SMS or incoming calls. signal-cli is primarily intended to be
used on servers to notify admins of important events. For this use-case, it has
a dbus interface, that can be used to send messages from any programming
language that has dbus bindings.