Installation

Linux & macOS

terminal
curl -fsSL https://bck.backternity.dev/install | sh

Windows

Download from releases and add to PATH.

Verify Installation

terminal
bck --version

Quick Start

Sender
terminal
bck send ./file.txt

Generates a code like 7-guitar-piano

Receiver
terminal
bck receive 7-guitar-piano

File is downloaded and decrypted automatically

Send & Receive

Send a file

terminal
bck send ./document.pdf

Send a directory

terminal
bck send ./my-project

Directories are automatically compressed (tar.gz) before transfer.

Exclude files

terminal
bck send ./project --exclude=node_modules --exclude=.git

Receive interactively

terminal
bck receive

Prompts for the transfer code if not provided.

Live Streaming

Stream data in real-time between machines. Perfect for logs, command output, or any piped data.

Stream (Sender)
terminal
tail -f /var/log/app.log | bck stream
Watch (Receiver)
terminal
bck watch 7-guitar-piano

More examples

terminal
# Save to file
bck watch 7-guitar-piano > output.log

# Filter with grep
bck watch 7-guitar-piano | grep ERROR

Options

FlagDescription
--excludeExclude files matching pattern
--code-lengthNumber of words in code (2-6, default: 3)
--relayCustom relay server URL
-v, --verboseVerbose output with progress

Security

PAKE (SPAKE2)
Password-authenticated key exchange
AES-256-GCM
Authenticated encryption
HKDF-SHA256
Key derivation
CRC32 + SHA-256
Integrity verification

The relay server never sees unencrypted data. All encryption happens locally before transmission.