dcp - Dat Copy

Remote file copy, powered by the Dat protocol.

dcp copies files between hosts on a network using the peer-to-peer Dat network. dcp can be seen as an alternative to tools like scp, removing the need to configure SSH access between hosts. This lets you transfer files between two remote hosts, without you needing to worry about the specifics of how said hosts reach each other and regardless of whether hosts are behind NATs.

dcp requires zero configuration and is secure, fast, and peer-to-peer.

WARNING - this is not production-ready software. Use at your own risk

Contents

• How dcp works
• Installation
• Usage
• Development

Example

Use cases

• Send files to multiple colleagues - just send the generated public key via chat and they can receive the files on their machine.
• Sync files between two physical computers on your local network, without needing to set up SSH access.
• Easily send files to a friend without needing to create a zip and upload it the cloud.
• Copy files to a remote server when you have shell access but not SSH, for example on a kubernetes pod.
• Share files between linux/macOS and Windows, which isn't exactly known for great SSH support.

How dcp works

dcp will create a dat archive for a specified set of files or directories and, using the generated public key, lets you download said archive from other hosts. Any data shared over the network is encrypted using the public key of the archive, meaning data access is limited to those who have access to said key. For more information on how Dat works, you can browse the docs or read their whitepaper.

Advantages over plain dat

dcp is designed to have an API that is more reminiscent of scp and rsync. The standard cli dat program requires the additional mental overhead of understanding how the underlying Dat protocol works. dat forces you to share a single whole folder, whilst with dcp you can copy an arbitrary set of paths. dat also pollutes the filesystem with metadata files, whereas with dcp these are kept in-memory instead.

Performance

You can expect dcp to transfer at a similar speed to both rsync and scp.

Here's a benchmark for moving a 396.12MB file from my personal computer to a remote server over my 50mpbs connection.

Method	Time
rsync	1m07s
scp	1m07s
dcp	1m10s

Installation

npm i -g dat-cp

Installing without npm

Alternatively, packaged binaries are available on the releases page. These bundle all dependencies into a single standalone binary.

Simply extract the zip and move the dcp[.exe] binary to a folder in your path, e.g. /usr/local/bin.

Usage

Usage: dcp [options] {files ... | key}

Dat Copy - remote file copy, powered by the dat protocol.

Options:
  -V, --version    output the version number
  -r, --recursive  recursively copy directories
  -n, --dry-run    show what files would have been copied
  --skip-prompt    automatically download without a prompt
  -v, --verbose    verbose mode - prints extra debugging messages
  -h, --help       output usage information

Example:

    Send files from host A:

        > dcp foo.txt bar.txt

    Receive files on host B:

        > dcp <generated public key>

Sending files

Pass an arbitrary set of files or directories to dcp to be copied. Copy the generated public key and use it to receive the files on a different host.

> dcp [-r] [-n] [-v] files ...

• Use -n/--dry-run to see what files will be sent
• Use -r/--recursive to recursively copy files within directories
• Use -v/--verbose to print extra debugging information

Receiving files

Invoke dcp with the generated public key to receive the copied files.

> dcp [-n] [-v] [--skip-prompt] <generated public key>

• Use -n/--dry-run to see what files will be received
• Use -v/--verbose to print extra debugging information
• Use --skip-prompt to skip the download prompt

Development

Install dependencies:

npm i

Run the tests:

npm t

Test the CLI executable

npm run cli -- foo.txt -v

Note the -- preceding the arguments.