ffsend is a command line Firefox Send client that's currently in alpha, available for Linux, macOS and Windows (with only macOS and Linux binaries being available right now).
With ffsend you can easily and securely share files from the command line, by making use of a Send, a Firefox test pilot project.
Firefox Send is a file sharing experiment by Mozilla, which allows sending encrypted files to other users. 'Send' can be installed on your own server, or you can use the Mozilla-hosted send.firefox.com. The latter officially supports files up to 1 GB (but I could upload a 2GB file, as mentioned by the ffsend description), with each link expiring after a configurable download count (defaulting to 1 download) or 24 hours, while also deleting all the files from the Send server. Read more about the Send Firefox Test Pilot.