# BackTunnel – Reverse SSH Folder Sharing Toolkit

Share and mount folders between Linux machines behind NAT/firewalls using two friendly commands.

## ✨ Commands

### `backtunnel-share`
Start a reverse SSH tunnel from the *sharing* machine for a limited time.

```bash
backtunnel-share /path/to/folder with remoteuser:remotehost for <duration> [options]
# or: remoteuser@remotehost
```

**Duration formats:** `30m`, `2h`, `1d` (passed to `timeout`)

**Options**
- `-p, --tunnel-port <PORT>`: Remote port to expose with `-R` (default: 2222)
- `-l, --local-ssh-port <PORT>`: Local sshd port to forward to (default: 22)
- `-i, --invite`: Print a ready-to-copy access command for the remote user
- `--invite-mount <PATH>`: Suggest mount point in the invite (default: `/mnt/remote-rssh`)
- `--invite-file <FILE>`: Also write the invite text (including unmount hint) to a file
- `--qr`: Render the invite as a QR code (requires `qrencode`)

**Examples**
```bash
# Share for 2h
backtunnel-share ~/projects with alice@vps.example.com for 2h

# Share and print a one-liner invite for chat
backtunnel-share ~/projects with alice@vps.example.com for 2h -i

# Share with custom ports and QR invite
backtunnel-share ~/projects with alice@vps.example.com for 1d -p 4422 -l 2222 -i --qr
```

The invite will look like this and can be pasted on the remote host:
```bash
backtunnel-access '/home/user/projects' from alice@vps.example.com -p 4422 -m '/mnt/remote-rssh'
```

Unmount on the remote side with:
```bash
fusermount -u /mnt/remote-rssh
```

### `backtunnel-access`
Mount a folder from the *remote* side via SSHFS.

```bash
backtunnel-access /path/to/folder from remoteuser:remotehost [options]
# or: remoteuser@remotehost
```

**Options**
- `-p, --port <PORT>`: Port on the remote host where the reverse tunnel listens (default: 2222)
- `-m, --mount-point <PATH>`: Local mount point (default: `/mnt/remote-rssh`)

---

## 🧰 Dolphin Service Menus

Two context actions for Dolphin:
- **Share via BackTunnel…** (right-click a folder on the sharing machine)
- **Access via BackTunnel…** (right-click a folder path on the remote machine)

Installed into:
- Plasma 6: `/usr/share/kio/servicemenus/`
- Plasma 5: `/usr/share/kservices5/ServiceMenus/`

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## 🔐 Requirements
- `ssh`, `sshfs`, `timeout`, `konsole`, `kdialog`
- Optional: 
  - `bash-completion`
  - `qrencode` (for QR-code invites)

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## 📦 Install
```bash
sudo bash scripts/install.sh
```
Uninstall:
```bash
sudo bash scripts/uninstall.sh
```

---

## 📖 Man Page
```bash
man backtunnel
```

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## 🧾 License
Licensed under **GNU GPL v3.0**. See `LICENSE`.