BackTunnel/README.md

# 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`)

---

## 📁 Profiles (named remotes)

BackTunnel supports **profiles** to simplify connections. Instead of typing
`user@host -p PORT -l PORT …` every time, you can define defaults and named remotes in:

📖 Example config: see [docs/profiles.ini.example](docs/profiles.ini.example)

System-wide default: /etc/backtunnel/profiles.ini (admins can edit)
Packaged example: /usr/share/backtunnel/profiles.ini

---

## 🧰 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/`

### 🖱️ Dolphin (GUI) Flow — Share with Invite

1. **Right-click a folder → “Share via BackTunnel…”**  
2. Enter **Remote** (`user@host` or `user:host`), choose **Duration**, **Tunnel port** (default `2222`), and **Local SSH port** (default `22`).  
3. When prompted:
   - **Print invite line for chat?** → Yes to get a one-liner your colleague can paste.
   - **Show QR code for the invite?** → Yes (requires `qrencode`) to display a terminal QR.
   - **Suggested mount point** → Accept `/mnt/remote-rssh` or set your own.
4. A terminal opens, shows the **invite** (and QR if selected), and keeps the share open for the chosen duration.  
   - Stop early with **Ctrl+C**.

**What the remote user does (on the remote host):**

```bash
# Paste the invite you sent them, e.g.:
backtunnel-access '/path/to/folder' from user@vps.example.com -p 2222 -m '/mnt/remote-rssh'
# Unmount when done:
fusermount -u /mnt/remote-rssh    # or: umount /mnt/remote-rssh
```

---

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

---

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

---

## 📦 Release checklist (BackTunnel v1.2.x)

1. **Version bump** (if needed) in docs/man where referenced (man page already shows `1.2`).  
2. **Tag the repo**:

```bash
   git tag -a v1.2.0 -m "BackTunnel 1.2.0"
   git push --tags
```

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

---

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