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+# µcp/ucp: µTP copy (very remote file transfer)
+
+This is basically a clone of SSH's scp command that uses the µTP (the Micro
+Transport Protocol) over UDP instead of passing data through the TCP SSH
+connection. SSH (and TCP) is used for authentication and setup, just like
+`mosh` does; the server-side ucp process is not a daemon and is not running
+continuously.
+
+The motivation for this tool is to get better bandwidth utilization over
+high-latency links with mild packet loss, while remaining well-behaved netizen.
+
+Just like `scp`, this program is based on the old `rcp` "protocol" and is very
+simple. There is no session resumption, or extra checksums or integrity checks,
+support for file metadata beyond old-school UNIX permissions, or anything like
+that. There is a bunch of overhead sending small files, so if you have a lot of
+those and a high-latency link you should probably `tar` things up first. There
+also isn't any compression, so you might want to `gzip` that tarball.
+
+### Usage
+
+The command must be installed on both the local and remote machines.
+
+To send a local file named `insurance.aes256` to the home directory of `robin`
+on `files.the-nsa.org`:
+
+    ucp insurance.aes256 robin@files.the-nsa.org:
+
+To copy a complete directory of files from the directory "~/everything/" on the
+remote server to a new folder `/tmp/img/` locally:
+
+    ucp -r robin@files.the-nsa.org:everything /tmp
+
+### rcp Protocol
+
+The `rcp` protocol is described in a
+[Jul 09, 2007 blog post by janp](https://blogs.oracle.com/janp/entry/how_the_scp_protocol_works),
+which is mirrored as text in the `doc` folder of this repo.
+