A Go-based SSH terminal emulator with session management, built on Fyne 2 GUI framework and the gopyte terminal emulation library.
The first fully-functional Fyne-based SSH terminal with session management, scrollback history, and text selection.
Hierarchical folder/session tree with search filter, connection status indicators, and multi-tab interface
htop running with full 256-color support, proper resize handling, and alternate screen buffer
CRUD interface for managing sessions and folders with full authentication configuration
- SSH connectivity with password and public key authentication
- Multi-tab terminal interface with tree-based session navigator
- Full terminal emulation via gopyte (VT100/ANSI parsing)
- Keyboard input routing to SSH sessions
- Dynamic terminal resize with proper SSH window-change signaling
- Full-screen applications (htop, vim, nano, etc.)
- 256-color support with proper color mapping
- Scrollback history (1000+ lines) with mouse wheel scrolling
- Text selection with clipboard support (double-click word, triple-click line)
- Tree-based session navigator with collapsible folders
- Right-click context menu on sessions (Connect, Edit)
- Session persistence via YAML configuration
- Session search/filter for quick access to devices
- Session editor with full CRUD operations
- Quick Connect dialog for ad-hoc connections
- SSH key authentication with encrypted key support
- Settings dialog with persistent configuration
- SSH agent support not fully implemented
- Host key verification not yet implemented
TetherSSH uses gopyte, a custom terminal emulation library written specifically for this project. Unlike the Fyne project's proof-of-concept terminal, gopyte provides:
- Full history buffer with configurable scrollback (default 1000 lines)
- Wide character support for CJK characters and emojis
- Alternate screen buffer for full-screen applications (vim, htop, less)
- Proper resize handling that syncs local screen, gopyte buffers, and SSH session
- Tree-based navigator with collapsible folders and session counts
- Right-click context menu for quick Connect or Edit
- Real-time search/filter - instantly find sessions by name, host, group, or device type
- Multiple concurrent SSH connections in tabs
- Visual connection status indicators
- One-click connect with automatic credential handling
- Password authentication - prompted on connect or stored in session
- SSH key authentication - supports RSA, ECDSA, Ed25519 keys
- Encrypted key support - passphrase prompts for protected keys
- Keyboard-interactive - for MFA/RADIUS environments (including YubiKey)
- Configurable per-session authentication type
Press the fast-forward button for ad-hoc connections without saving a session:
- Enter host, port, username
- Choose Password or SSH Key authentication
- Default key path: ~/.ssh/id_rsa
- Optional key passphrase for encrypted keys
Press the gear button to open the full session manager:
- Folders panel - organize sessions into groups
- Sessions panel - view/edit sessions in selected folder
- Add/Edit/Delete - full CRUD operations
- Import - load sessions from other YAML files
- Export - save current configuration
- Device metadata fields (type, vendor, model) for network equipment
All configuration is stored in ~/.velocitycmd/ for consistency across the VelociTerm ecosystem:
- Sessions:
~/.velocitycmd/sessions/sessions.yaml - Settings:
~/.velocitycmd/settings.json - Logs:
~/.velocitycmd/logs/(when logging is enabled)
# TetherSSH Sessions File
# Auth types: password, publickey, keyboard-interactive
- folder_name: Production
sessions:
- display_name: web-server-01
host: 10.0.1.10
port: "22"
username: admin
auth_type: publickey
key_path: ~/.ssh/id_rsa
DeviceType: linux
- folder_name: Lab
sessions:
- display_name: cisco-router
host: 172.16.1.1
port: "22"
username: admin
auth_type: password
DeviceType: cisco_ios
Vendor: CiscoPress the gear icon in the toolbar to open the Settings dialog. Settings are persisted to ~/.velocitycmd/settings.json.
| Setting | Description | Default |
|---|---|---|
| Row Offset | Adjust terminal row calculation (increase for Retina/HiDPI displays) | 2 |
| Column Offset | Adjust terminal column calculation | 0 |
| Font Size | Terminal font size in points (not yet implemented) | 12 |
| Scrollback Lines | History buffer size (not yet implemented) | 1000 |
| Copy on Select | Auto-copy selected text to clipboard (not yet implemented) | Off |
| Setting | Description | Default |
|---|---|---|
| Dark Theme | Toggle dark/light theme | On |
| Remember Window Size | Restore window dimensions on startup | On |
| Setting | Description | Default |
|---|---|---|
| Default SSH Key | Default key path for new sessions | ~/.ssh/id_rsa |
| Default Port | Default SSH port | 22 |
| Default Username | Pre-fill username for new sessions | (empty) |
| Connection Timeout | SSH connection timeout in seconds | 30 |
| Keepalive Interval | SSH keepalive interval in seconds | 60 |
| Setting | Description | Default |
|---|---|---|
| Enable Logging | Write session output to log files | Off |
| Log Directory | Directory for session logs | ~/.velocitycmd/logs |
| Timestamp Logs | Prefix log entries with timestamps | On |
Log filename format: {session_name}_{YYYYMMDD_HHMMSS}.log
tetherssh/
├── cli/
│ ├── main.go # Application entry, window setup
│ ├── paths.go # Centralized path management (~/.velocitycmd)
│ ├── session_manager.go # Tree navigator, search, tab management
│ ├── session_persistence.go # YAML load/save, SessionStore
│ ├── session_editor.go # CRUD modal dialog
│ ├── settings.go # Application settings dialog
│ ├── ssh_backend.go # SSH client, auth chain, SSHTerminalWidget
│ ├── terminal_widget.go # NativeTerminalWidget - core terminal UI
│ ├── terminal_pty.go # Local PTY support, WriteToPTY, history
│ ├── terminal_events.go # Keyboard/mouse event handling
│ ├── terminal_events_bus.go # Event bus for terminal events
│ ├── terminal_display.go # TextGrid rendering, viewport calculation
│ ├── terminal_selection.go # Text selection and clipboard
│ ├── terminal_containers.go # Custom container widgets
│ ├── tappable_tree_node.go # Right-click support for tree nodes
│ ├── theme.go # Fyne theme, color mappings
│ ├── pty_unix.go # Unix PTY implementation
│ └── pty_windows.go # Windows PTY implementation
├── internal/
│ └── gopyte/ # Terminal emulation library
│ ├── screen.go # Base screen buffer (NativeScreen)
│ ├── screen_interface.go # Screen interface definitions
│ ├── history_screen.go # Scrollback history management
│ ├── wide_char_screen.go # Wide character support
│ ├── alternative_screen.go # Alternate screen buffer (vim, htop)
│ ├── streams.go # ANSI escape sequence parser
│ ├── escape.go # Escape sequence definitions
│ ├── control.go # Control character handling
│ ├── graphics.go # SGR/graphics attributes
│ ├── modes.go # Terminal mode handling
│ ├── charset.go # Character set support
│ └── gopyte_test/ # Test suite
├── screenshots/
│ ├── htop.png
│ ├── session_detail.png
│ └── session_manager.png
├── go.mod
├── go.sum
├── LICENSE
└── README.md
- Go 1.21 or later
- GCC compiler (required for CGO/OpenGL):
- Windows: Install TDM-GCC from https://jmeubank.github.io/tdm-gcc/ (MinGW-w64 based)
- Linux:
sudo apt install build-essential(Debian/Ubuntu) or equivalent - macOS:
xcode-select --install
# Linux/macOS - run directly
go run -tags='!windows' ./cli
# Linux/macOS - build with debug symbols
go build -tags='!windows' -o tetherssh ./cli
# Windows - run directly
go run ./cli
# Windows - build with debug symbols
go build -o tetherssh.exe ./cliStripped binaries are approximately 50% smaller with no debug symbols.
# Linux/macOS
go build -tags='!windows' -ldflags="-s -w" -o tetherssh ./cli
# Windows
go build -ldflags="-s -w" -o tetherssh.exe ./cliCross-compiling Fyne apps requires CGO, which complicates cross-builds. Build natively on each target platform, or use fyne-cross with Docker:
# Install fyne-cross
go install github.com/fyne-io/fyne-cross@latest
# Build for Windows from Linux/macOS
fyne-cross windows -arch=amd64 ./cli
# Build for Linux from macOS/Windows
fyne-cross linux -arch=amd64 ./cli| Build Type | Size |
|---|---|
| Debug (full symbols) | ~53 MB |
| Release (stripped) | ~26 MB |
| Zipped release | ~12 MB |
fyne.io/fyne/v2 # GUI framework
golang.org/x/crypto/ssh # SSH client
github.com/creack/pty # Local PTY (Unix)
github.com/mattn/go-runewidth # Wide character width calculation
github.com/google/uuid # Tab/session unique IDs
gopkg.in/yaml.v3 # Session persistence
TetherSSH stores all configuration in ~/.velocitycmd/ for consistency with the VelociTerm ecosystem:
| File | Purpose |
|---|---|
~/.velocitycmd/sessions/sessions.yaml |
Session definitions |
~/.velocitycmd/settings.json |
Application settings |
~/.velocitycmd/logs/ |
Session logs (when enabled) |
On first run, a stub sessions file is created with example entries.
| YAML Value | Description |
|---|---|
password |
Prompt for password on connect |
publickey |
Use SSH key from key_path |
keyboard-interactive |
MFA/RADIUS environments |
The ~ character is expanded to the user's home directory:
~/.ssh/id_rsabecomes/home/username/.ssh/id_rsa(Linux)~/.ssh/id_rsabecomes/Users/username/.ssh/id_rsa(macOS)~/.ssh/id_rsabecomesC:\Users\username\.ssh\id_rsa(Windows)
- Fix vim/htop resize issues
- Implement resize callback pattern
- Post-connect resize sync
- Buffer bounds safety in gopyte
- Session persistence (YAML config)
- Public key authentication
- Encrypted key passphrase support
- Session search/filter
- Session editor with CRUD
- Quick Connect dialog
- Tree-based session navigator
- Settings dialog with persistence
- Right-click context menu
- Implement SSH agent support
- Add host key verification with known_hosts
- Clean up debug logging
- More cross-platform testing (Windows, Linux, macOS)
- Per-session logging (raw/timestamped output to file)
- Log viewer/browser
- Encrypted credentials manager (AES-256-GCM)
- Master password unlock flow
- Credential references in sessions (decouple passwords from YAML)
- Split panes (horizontal/vertical)
- Find in terminal output
- Clickable URLs
- Command snippets/macros
- SFTP file browser integration
- Port forwarding UI
- Jump host/proxy support
- Session import from PuTTY/SecureCRT
gopyte is a terminal emulation library built specifically for TetherSSH. It provides:
- NativeScreen: Base screen buffer
- HistoryScreen: Adds scrollback history
- WideCharScreen: Adds wide character support and alternate screen buffer
- VT100/ANSI parsing via Stream.Feed()
- Scrollback history with linked list storage
- Alternate screen buffer for vim, htop, less, etc.
- Wide character support for CJK and emojis
- Resize handling that preserves content and history
- Cursor movement (CUP, CUU, CUD, CUF, CUB)
- Erase operations (ED, EL)
- SGR attributes (colors, bold, underline, etc.)
- Scroll regions (DECSTBM)
- Alternate screen (DECSET/DECRST 1049)
- Window title (OSC 0, 1, 2)
- Secure Cartography: https://github.com/scottpeterman/secure_cartography - Network discovery and topology mapping
- TerminalTelemetry: https://pypi.org/project/terminaltelemetry/ - PyQt6-based SSH terminal with real-time monitoring
- VelociTerm: https://github.com/scottpeterman/velociterm - Web-based SSH terminal with NetBox integration
MIT License - See LICENSE file
Last updated: December 1, 2025
Author: Scott Peterman