bashdrop

bashdrop is a tiny one-shot file transfer tool.

It is designed for situations where the sender and receiver only have Bash and raw TCP via /dev/tcp.

That means: no scp, no rsync, no wormhole, no croc, no curl, no wget, no netcat. Just Bash. (Optionally openssl and sha256sum for integrity and encryption modes.)

A temporary Python relay server is required somewhere on the internet:

• It can be bootstrapped automatically over SSH (with bashdrop).
• Or started manually.

Note

The SSH/scp dependency exists only to set up the server. Neither the sender nor the receiver need them — they just run Bash commands.

Files

• bashdrop — the main script. Copies bashdrop-server.py to a remote machine over SSH and runs it there.
• bashdrop-server.py — the Python server that handles one upload and one download. Can also be run directly if you're already on the host.

Installation with Nix

Test it out without installation:

nix run . -- <ssh-target> <public-domain-or-ip> [filename] [password]

Install it permanently:

nix profile add github:fabian-thomas/bashdrop

Usage

Step 1: Start a Relay Server

You need a reachable server somewhere (e.g. a VPS). There are two ways to start the relay:

1. Bootstrap via SSH (automatic):

   bashdrop [-p PORT] <ssh-target> <public-domain-or-ip> [filename] [password]

   This uses ssh/scp to copy and start bashdrop-server.py.

   Example:

   bashdrop user@myserver my-domain-or-ip.com

2. Manual start (no SSH needed): If you already have access to the server shell:

   bashdrop-server.py [-p PORT] <public-host-or-ip> [filename] [password]

Important

The <ssh-target> and <public-domain-or-ip> must point to the same machine.

• <ssh-target> → how you connect via SSH (e.g. user@myserver)
• <public-domain-or-ip> → how sender/receiver connect (e.g. my-domain-or-ip.com)

Step 2: Send/Receive the File

Once the server is running, it prints ready-to-use Sender and Receiver commands in three modes:

1. Plain Bash — just /dev/tcp
2. Plain + Integrity Check — /dev/tcp with sha256sum verification
3. Encrypted + Integrity Check — openssl enc -aes-256-cbc -pbkdf2 with sha256sum

These commands require only:

• Bash + /dev/tcp
• (optional) sha256sum
• (optional) openssl

No ssh, no scp.

Options

• -p PORT: TCP port to listen on (default: 9000).
• filename: filename shown in the copy-paste commands (default: file).
• password: optional, used only for the encrypted mode (default: random).

Port 9000 is used by default. Ensure port forwarding / firewall rules allow access.

Minimal Send/Recv Example

Sender:

cat >/dev/tcp/my-domain-or-ip.com/9000 < myfile.txt

Receiver:

cat </dev/tcp/my-domain-or-ip.com/9000 > myfile.txt

Remember: these commands only work while the server is running to relay the file.