Replace Go SSH library with native ssh command

Major rewrite to use native ssh command instead of Go SSH library:

BREAKING CHANGE: Now requires ssh command in PATH

Benefits:
- Full SSH feature support including ProxyCommand
- Works with SSH containers and jump hosts
- Supports all SSH authentication methods
- Consistent behavior with terminal SSH
- No more custom SSH client implementation

Changes:
- Port detection now uses 'ssh hostname command'
- Port forwarding uses 'ssh -L localport:localhost:remoteport hostname'
- Connection testing uses native ssh command
- Removed golang.org/x/crypto/ssh dependency
- Updated documentation to reflect SSH compatibility

This fixes issues with SSH containers that require ProxyCommand
and provides full compatibility with user SSH configurations.

Co-authored-by: Ona <no-reply@ona.com>

README.md

@@ -6,10 +6,11 @@ A terminal user interface (TUI) application for SSH port forwarding that reads f
 
 - **SSH Config Integration**: Automatically reads from `~/.ssh/config`
 - **Include Support**: Supports SSH config `Include` directive with glob patterns
+- **Full SSH Compatibility**: Uses native `ssh` command - supports ProxyCommand, jump hosts, and all SSH features
 - **Interactive Host Selection**: Choose from configured SSH hosts using arrow keys
 - **Automatic Port Detection**: Scans remote host for listening ports using `netstat`, `ss`, or `lsof`
 - **Manual Port Forwarding**: Option to manually specify remote ports with improved UI
-- **Real-time Port Forwarding**: Creates SSH tunnels similar to VSCode's remote SSH port forwarding
+- **Real-time Port Forwarding**: Creates SSH tunnels using `ssh -L` command
 - **Clean TUI Interface**: Built with Bubble Tea for a smooth terminal experience
 
 ## Installation
@@ -95,9 +96,13 @@ Relative paths in includes are resolved relative to `~/.ssh/` directory, matchin
 
 ## Authentication
 
-The application supports:
+The application uses the native `ssh` command, so it supports all SSH authentication methods:
 - SSH key-based authentication (using IdentityFile from config)
 - SSH agent authentication (if SSH_AUTH_SOCK is set)
+- ProxyCommand for jump hosts and SSH containers
+- All other SSH configuration options (ControlMaster, etc.)
+
+This means if you can connect with `ssh hostname`, kport will work too!
 
 ## Requirements
 
@@ -115,10 +120,10 @@ The application supports:
 ## How It Works
 
 1. **Config Parsing**: Reads and parses your SSH config file to extract host information
-2. **SSH Connection**: Establishes SSH connection using configured authentication methods
-3. **Port Detection**: Runs commands like `netstat -tlnp` on the remote host to find listening ports
-4. **Port Forwarding**: Creates local TCP listener that forwards connections through SSH tunnel
-5. **Traffic Relay**: Copies data bidirectionally between local and remote connections
+2. **SSH Connection**: Uses native `ssh` command with all your configured options
+3. **Port Detection**: Runs commands like `netstat -tlnp` on the remote host via SSH to find listening ports
+4. **Port Forwarding**: Uses `ssh -L localport:localhost:remoteport hostname` for tunneling
+5. **Full Compatibility**: Works with ProxyCommand, jump hosts, SSH containers, and all SSH features
 
 ## Expected Behavior
 
@@ -135,11 +140,17 @@ The application gracefully handles connection failures and allows you to:
 
 ## Limitations
 
-- Password authentication is not implemented (use SSH keys or agent)
-- Host key verification uses `InsecureIgnoreHostKey` (should be improved for production use)
+- Requires `ssh` command to be available in PATH
 - Port detection requires `netstat`, `ss`, or `lsof` on the remote host
 - Connection failures are expected for non-existent or unreachable hosts
 
+## Advantages of Using Native SSH Command
+
+- **Full SSH Feature Support**: ProxyCommand, ControlMaster, jump hosts, etc.
+- **Consistent Behavior**: Same authentication and connection logic as your terminal
+- **SSH Container Support**: Works with containers that require ProxyCommand
+- **No Additional Setup**: If `ssh hostname` works, kport works too
+
 ## License
 
 MIT License

main.go

@@ -3,6 +3,9 @@ package main
 import (
 	"fmt"
 	"os"
+	"os/exec"
+	"os/user"
+	"strings"
 )
 
 func main() {
@@ -90,9 +93,52 @@ func testConnection(hostName string) {
 	}
 	fmt.Println("")
 	
+	// Expand shell variables in the host config
+	expandedHost := *host
+	expandedHost.User = expandShellVars(host.User)
+	expandedHost.Identity = expandShellVars(host.Identity)
+	
+	if expandedHost.User != host.User {
+		fmt.Printf("Expanded user: %s -> %s\n", host.User, expandedHost.User)
+	}
+	if expandedHost.Identity != host.Identity {
+		fmt.Printf("Expanded identity: %s -> %s\n", host.Identity, expandedHost.Identity)
+	}
+	if expandedHost.User != host.User || expandedHost.Identity != host.Identity {
+		fmt.Println("")
+	}
+	
+	// Test SSH connection using ssh command (supports all SSH features)
+	fmt.Println("Testing SSH connection...")
+	fmt.Printf("Running: ssh -o ConnectTimeout=10 -o BatchMode=yes %s echo 'connection test'\n", expandedHost.Name)
+	
+	sshCmd := exec.Command("ssh", "-o", "ConnectTimeout=10", "-o", "BatchMode=yes", expandedHost.Name, "echo", "connection test")
+	output, err := sshCmd.Output()
+	if err != nil {
+		fmt.Printf("❌ SSH connection failed: %v\n", err)
+		fmt.Println("")
+		fmt.Println("Common SSH connection issues:")
+		fmt.Println("- SSH keys not set up or not in SSH agent")
+		fmt.Println("- Wrong username or hostname")
+		fmt.Println("- Host key verification failed")
+		fmt.Println("- SSH server not running or configured differently")
+		fmt.Println("- ProxyCommand or other SSH config issues")
+		fmt.Println("")
+		fmt.Println("Try running the SSH command manually:")
+		fmt.Printf("  ssh %s\n", expandedHost.Name)
+		return
+	}
+	
+	if strings.TrimSpace(string(output)) == "connection test" {
+		fmt.Printf("✅ SSH connection successful!\n")
+	} else {
+		fmt.Printf("⚠️  SSH connection partially successful but got unexpected output: %s\n", string(output))
+	}
+	fmt.Println("")
+	
 	// Test port detection
 	fmt.Println("Testing port detection...")
-	ports, err := detectRemotePorts(*host)
+	ports, err := detectRemotePorts(expandedHost)
 	if err != nil {
 		fmt.Printf("❌ Port detection failed: %v\n", err)
 		fmt.Println("")
@@ -108,3 +154,32 @@ func testConnection(hostName string) {
 	fmt.Println("")
 	fmt.Println("You can still use manual port forwarding in the TUI even if port detection fails.")
 }
+
+// expandShellVars expands shell variables in SSH config values
+func expandShellVars(value string) string {
+	if value == "" {
+		return value
+	}
+	
+	// Handle $(whoami) and $USER
+	if strings.Contains(value, "$(whoami)") || strings.Contains(value, "$USER") {
+		currentUser, err := user.Current()
+		if err == nil {
+			value = strings.ReplaceAll(value, "$(whoami)", currentUser.Username)
+			value = strings.ReplaceAll(value, "$USER", currentUser.Username)
+		}
+	}
+	
+	// Handle $HOME and ~/
+	if strings.Contains(value, "$HOME") || strings.HasPrefix(value, "~/") {
+		homeDir, err := os.UserHomeDir()
+		if err == nil {
+			value = strings.ReplaceAll(value, "$HOME", homeDir)
+			if strings.HasPrefix(value, "~/") {
+				value = strings.Replace(value, "~/", homeDir+"/", 1)
+			}
+		}
+	}
+	
+	return value
+}

port_detection.go

@@ -2,15 +2,13 @@ package main
 
 import (
 	"fmt"
-	"net"
 	"os"
+	"os/exec"
 	"sort"
 	"strconv"
 	"strings"
-	"time"
 
 	tea "github.com/charmbracelet/bubbletea"
-	"golang.org/x/crypto/ssh"
 )
 
 // PortsDetectedMsg is sent when ports are detected
@@ -38,51 +36,8 @@ func DetectPorts(host SSHHost) tea.Cmd {
 	}
 }
 
-// detectRemotePorts connects to the remote host and detects open ports
+// detectRemotePorts connects to the remote host and detects open ports using ssh command
 func detectRemotePorts(host SSHHost) ([]int, error) {
-	// Create SSH client configuration
-	config := &ssh.ClientConfig{
-		User: host.User,
-		Auth: []ssh.AuthMethod{},
-		HostKeyCallback: ssh.InsecureIgnoreHostKey(), // In production, use proper host key verification
-		Timeout:         5 * time.Second, // Shorter timeout
-	}
-
-	// Add key-based authentication if identity file is specified
-	if host.Identity != "" {
-		key, err := loadPrivateKey(host.Identity)
-		if err == nil {
-			config.Auth = append(config.Auth, ssh.PublicKeys(key))
-		}
-	}
-
-	// Add SSH agent authentication if available
-	if agentAuth, err := sshAgentAuth(); err == nil {
-		config.Auth = append(config.Auth, agentAuth)
-	}
-
-	// If no auth methods available, add a dummy one to avoid empty auth
-	if len(config.Auth) == 0 {
-		config.Auth = append(config.Auth, ssh.PasswordCallback(func() (string, error) {
-			return "", fmt.Errorf("no authentication methods available")
-		}))
-	}
-
-	// Connect to the remote host
-	addr := net.JoinHostPort(host.Hostname, host.Port)
-	client, err := ssh.Dial("tcp", addr, config)
-	if err != nil {
-		return nil, fmt.Errorf("failed to connect to %s (%s): %w", host.Name, addr, err)
-	}
-	defer client.Close()
-
-	// Run netstat command to detect listening ports
-	session, err := client.NewSession()
-	if err != nil {
-		return nil, fmt.Errorf("failed to create SSH session: %w", err)
-	}
-	defer session.Close()
-
 	// Try different commands to detect listening ports
 	commands := []string{
 		"netstat -tlnp 2>/dev/null | grep LISTEN | awk '{print $4}' | cut -d: -f2 | sort -n | uniq",
@@ -91,23 +46,26 @@ func detectRemotePorts(host SSHHost) ([]int, error) {
 	}
 
 	var output []byte
+	var err error
+
 	for _, cmd := range commands {
-		session, err = client.NewSession()
-		if err != nil {
-			continue
-		}
+		fmt.Fprintf(os.Stderr, "Debug: Running command on %s: %s\n", host.Name, cmd)
 		
-		output, err = session.Output(cmd)
-		session.Close()
+		// Use ssh command directly - this supports all SSH features including ProxyCommand
+		sshCmd := exec.Command("ssh", "-o", "ConnectTimeout=10", "-o", "BatchMode=yes", host.Name, cmd)
 		
+		output, err = sshCmd.Output()
 		if err == nil && len(output) > 0 {
+			fmt.Fprintf(os.Stderr, "Debug: Command succeeded, got output\n")
 			break
 		}
+		fmt.Fprintf(os.Stderr, "Debug: Command failed: %v\n", err)
 	}
 
 	if err != nil || len(output) == 0 {
+		fmt.Fprintf(os.Stderr, "Debug: All port detection commands failed, trying common ports\n")
 		// Fallback: try common ports
-		return detectCommonPorts(client), nil
+		return detectCommonPorts(host), nil
 	}
 
 	// Parse the output to extract port numbers
@@ -133,56 +91,29 @@ func detectRemotePorts(host SSHHost) ([]int, error) {
 	return ports, nil
 }
 
-// detectCommonPorts tries to detect common ports by attempting connections
-func detectCommonPorts(client *ssh.Client) []int {
+// detectCommonPorts tries to detect common ports by testing connections through SSH
+func detectCommonPorts(host SSHHost) []int {
 	commonPorts := []int{80, 443, 3000, 3001, 4000, 5000, 8000, 8080, 8443, 9000}
 	var openPorts []int
 
+	fmt.Fprintf(os.Stderr, "Debug: Testing common ports on %s\n", host.Name)
+
 	for _, port := range commonPorts {
-		// Try to create a connection to the port through the SSH tunnel
-		conn, err := client.Dial("tcp", fmt.Sprintf("localhost:%d", port))
-		if err == nil {
-			conn.Close()
+		// Test if port is open using SSH to run a quick connection test
+		cmd := fmt.Sprintf("timeout 1 bash -c '</dev/tcp/localhost/%d' 2>/dev/null && echo 'open' || echo 'closed'", port)
+		sshCmd := exec.Command("ssh", "-o", "ConnectTimeout=5", "-o", "BatchMode=yes", host.Name, cmd)
+		
+		output, err := sshCmd.Output()
+		if err == nil && strings.TrimSpace(string(output)) == "open" {
 			openPorts = append(openPorts, port)
+			fmt.Fprintf(os.Stderr, "Debug: Port %d is open\n", port)
 		}
 	}
 
 	return openPorts
 }
 
-// loadPrivateKey loads a private key from file
-func loadPrivateKey(keyPath string) (ssh.Signer, error) {
-	// Expand tilde to home directory
-	if strings.HasPrefix(keyPath, "~/") {
-		homeDir, err := getHomeDir()
-		if err != nil {
-			return nil, err
-		}
-		keyPath = strings.Replace(keyPath, "~", homeDir, 1)
-	}
 
-	keyBytes, err := readFile(keyPath)
-	if err != nil {
-		return nil, fmt.Errorf("failed to read private key file: %w", err)
-	}
-
-	key, err := ssh.ParsePrivateKey(keyBytes)
-	if err != nil {
-		return nil, fmt.Errorf("failed to parse private key: %w", err)
-	}
-
-	return key, nil
-}
-
-// getHomeDir returns the user's home directory
-func getHomeDir() (string, error) {
-	return os.UserHomeDir()
-}
-
-// readFile reads a file and returns its contents
-func readFile(path string) ([]byte, error) {
-	return os.ReadFile(path)
-}
 
 // removeDuplicates removes duplicate integers from a slice
 func removeDuplicates(slice []int) []int {

port_forwarder.go

@@ -2,17 +2,13 @@ package main
 
 import (
 	"fmt"
-	"io"
 	"net"
 	"os"
-	"path/filepath"
+	"os/exec"
 	"strconv"
 	"sync"
-	"time"
 
 	tea "github.com/charmbracelet/bubbletea"
-	"golang.org/x/crypto/ssh"
-	"golang.org/x/crypto/ssh/agent"
 )
 
 // ForwardingStartedMsg is sent when port forwarding starts
@@ -21,29 +17,29 @@ type ForwardingStartedMsg struct {
 	RemotePort int
 }
 
-// PortForwarder manages SSH port forwarding
+// PortForwarder manages SSH port forwarding using ssh command
 type PortForwarder struct {
-	sshClient    *ssh.Client
+	hostName     string
 	localPort    int
 	remotePort   int
-	listener     net.Listener
+	sshCmd       *exec.Cmd
 	stopChan     chan struct{}
 	wg           sync.WaitGroup
 	isRunning    bool
 	mu           sync.Mutex
 }
 
-// NewPortForwarder creates a new port forwarder
-func NewPortForwarder(sshClient *ssh.Client, localPort, remotePort int) *PortForwarder {
+// NewPortForwarder creates a new port forwarder using ssh command
+func NewPortForwarder(hostName string, localPort, remotePort int) *PortForwarder {
 	return &PortForwarder{
-		sshClient:  sshClient,
+		hostName:   hostName,
 		localPort:  localPort,
 		remotePort: remotePort,
 		stopChan:   make(chan struct{}),
 	}
 }
 
-// Start starts the port forwarding
+// Start starts the port forwarding using ssh command
 func (pf *PortForwarder) Start() error {
 	pf.mu.Lock()
 	defer pf.mu.Unlock()
@@ -52,18 +48,28 @@ func (pf *PortForwarder) Start() error {
 		return fmt.Errorf("port forwarding already running")
 	}
 
-	// Create local listener
-	listener, err := net.Listen("tcp", fmt.Sprintf("localhost:%d", pf.localPort))
-	if err != nil {
-		return fmt.Errorf("failed to create local listener: %w", err)
+	// Use ssh command with -L flag for local port forwarding
+	// Format: ssh -L localport:localhost:remoteport hostname
+	pf.sshCmd = exec.Command("ssh", 
+		"-L", fmt.Sprintf("%d:localhost:%d", pf.localPort, pf.remotePort),
+		"-N", // Don't execute remote command, just forward ports
+		"-o", "ExitOnForwardFailure=yes", // Exit if port forwarding fails
+		"-o", "ServerAliveInterval=30", // Keep connection alive
+		"-o", "ServerAliveCountMax=3",
+		pf.hostName)
+
+	fmt.Fprintf(os.Stderr, "Debug: Starting SSH command: %s\n", pf.sshCmd.String())
+
+	// Start the SSH command
+	if err := pf.sshCmd.Start(); err != nil {
+		return fmt.Errorf("failed to start SSH port forwarding: %w", err)
 	}
 
-	pf.listener = listener
 	pf.isRunning = true
 
-	// Start accepting connections
+	// Monitor the SSH process
 	pf.wg.Add(1)
-	go pf.acceptConnections()
+	go pf.monitorSSH()
 
 	return nil
 }
@@ -80,78 +86,34 @@ func (pf *PortForwarder) Stop() {
 	pf.isRunning = false
 	close(pf.stopChan)
 
-	if pf.listener != nil {
-		pf.listener.Close()
+	// Kill the SSH process
+	if pf.sshCmd != nil && pf.sshCmd.Process != nil {
+		fmt.Fprintf(os.Stderr, "Debug: Stopping SSH port forwarding\n")
+		pf.sshCmd.Process.Kill()
 	}
 
 	pf.wg.Wait()
 }
 
-// acceptConnections accepts and handles incoming connections
-func (pf *PortForwarder) acceptConnections() {
+// monitorSSH monitors the SSH process
+func (pf *PortForwarder) monitorSSH() {
 	defer pf.wg.Done()
 
-	for {
-		select {
-		case <-pf.stopChan:
-			return
-		default:
-			// Set a timeout for Accept to avoid blocking indefinitely
-			if tcpListener, ok := pf.listener.(*net.TCPListener); ok {
-				tcpListener.SetDeadline(time.Now().Add(1 * time.Second))
-			}
-
-			conn, err := pf.listener.Accept()
-			if err != nil {
-				// Check if it's a timeout error and continue
-				if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
-					continue
-				}
-				// If we're stopping, ignore the error
-				select {
-				case <-pf.stopChan:
-					return
-				default:
-					continue
-				}
-			}
-
-			// Handle the connection in a separate goroutine
-			pf.wg.Add(1)
-			go pf.handleConnection(conn)
+	// Wait for the SSH command to finish or be stopped
+	select {
+	case <-pf.stopChan:
+		// We were asked to stop
+		return
+	default:
+		// Wait for SSH command to finish
+		if err := pf.sshCmd.Wait(); err != nil {
+			fmt.Fprintf(os.Stderr, "Debug: SSH command finished with error: %v\n", err)
+		} else {
+			fmt.Fprintf(os.Stderr, "Debug: SSH command finished successfully\n")
 		}
 	}
 }
 
-// handleConnection handles a single connection
-func (pf *PortForwarder) handleConnection(localConn net.Conn) {
-	defer pf.wg.Done()
-	defer localConn.Close()
-
-	// Create connection to remote host through SSH
-	remoteConn, err := pf.sshClient.Dial("tcp", fmt.Sprintf("localhost:%d", pf.remotePort))
-	if err != nil {
-		return
-	}
-	defer remoteConn.Close()
-
-	// Copy data between connections
-	var wg sync.WaitGroup
-	wg.Add(2)
-
-	go func() {
-		defer wg.Done()
-		io.Copy(localConn, remoteConn)
-	}()
-
-	go func() {
-		defer wg.Done()
-		io.Copy(remoteConn, localConn)
-	}()
-
-	wg.Wait()
-}
-
 // StartPortForwarding starts port forwarding for a specific port
 func StartPortForwarding(host SSHHost, remotePort int) tea.Cmd {
 	return func() tea.Msg {
@@ -165,18 +127,9 @@ func StartPortForwarding(host SSHHost, remotePort int) tea.Cmd {
 		}
 		fmt.Fprintf(os.Stderr, "Debug: Found available local port: %d\n", localPort)
 
-		// Create SSH client
-		client, err := createSSHClient(host)
-		if err != nil {
-			fmt.Fprintf(os.Stderr, "Debug: Failed to create SSH client: %v\n", err)
-			return ErrorMsg{Error: fmt.Errorf("failed to connect to %s: %w", host.Name, err)}
-		}
-		fmt.Fprintf(os.Stderr, "Debug: SSH client created successfully\n")
-
-		// Create and start port forwarder
-		forwarder := NewPortForwarder(client, localPort, remotePort)
+		// Create and start port forwarder using ssh command
+		forwarder := NewPortForwarder(host.Name, localPort, remotePort)
 		if err := forwarder.Start(); err != nil {
-			client.Close()
 			fmt.Fprintf(os.Stderr, "Debug: Failed to start port forwarder: %v\n", err)
 			return ErrorMsg{Error: fmt.Errorf("failed to start port forwarding: %w", err)}
 		}
@@ -213,18 +166,9 @@ func StartManualPortForwarding(host SSHHost, portStr string) tea.Cmd {
 		}
 		fmt.Fprintf(os.Stderr, "Debug: Found available local port: %d\n", localPort)
 
-		// Create SSH client
-		client, err := createSSHClient(host)
-		if err != nil {
-			fmt.Fprintf(os.Stderr, "Debug: Failed to create SSH client: %v\n", err)
-			return ErrorMsg{Error: fmt.Errorf("failed to connect to %s: %w", host.Name, err)}
-		}
-		fmt.Fprintf(os.Stderr, "Debug: SSH client created successfully\n")
-
-		// Create and start port forwarder
-		forwarder := NewPortForwarder(client, localPort, remotePort)
+		// Create and start port forwarder using ssh command
+		forwarder := NewPortForwarder(host.Name, localPort, remotePort)
 		if err := forwarder.Start(); err != nil {
-			client.Close()
 			fmt.Fprintf(os.Stderr, "Debug: Failed to start port forwarder: %v\n", err)
 			return ErrorMsg{Error: fmt.Errorf("failed to start port forwarding: %w", err)}
 		}
@@ -237,78 +181,7 @@ func StartManualPortForwarding(host SSHHost, portStr string) tea.Cmd {
 	}
 }
 
-// createSSHClient creates an SSH client for the given host
-func createSSHClient(host SSHHost) (*ssh.Client, error) {
-	config := &ssh.ClientConfig{
-		User: host.User,
-		Auth: []ssh.AuthMethod{},
-		HostKeyCallback: ssh.InsecureIgnoreHostKey(), // In production, use proper host key verification
-		Timeout:         10 * time.Second, // Longer timeout for better reliability
-	}
 
-	// Add key-based authentication if identity file is specified
-	if host.Identity != "" {
-		fmt.Fprintf(os.Stderr, "Debug: Trying identity file: %s\n", host.Identity)
-		key, err := loadPrivateKey(host.Identity)
-		if err == nil {
-			config.Auth = append(config.Auth, ssh.PublicKeys(key))
-			fmt.Fprintf(os.Stderr, "Debug: Added key-based auth\n")
-		} else {
-			fmt.Fprintf(os.Stderr, "Debug: Failed to load identity file: %v\n", err)
-		}
-	}
-
-	// Add SSH agent authentication
-	if agentAuth, err := sshAgentAuth(); err == nil {
-		config.Auth = append(config.Auth, agentAuth)
-		fmt.Fprintf(os.Stderr, "Debug: Added SSH agent auth\n")
-	} else {
-		fmt.Fprintf(os.Stderr, "Debug: SSH agent not available: %v\n", err)
-	}
-
-	// Try to load default SSH keys if no specific identity is set
-	if host.Identity == "" {
-		defaultKeys := []string{"id_rsa", "id_ecdsa", "id_ed25519"}
-		homeDir, err := os.UserHomeDir()
-		if err == nil {
-			for _, keyName := range defaultKeys {
-				keyPath := filepath.Join(homeDir, ".ssh", keyName)
-				if key, err := loadPrivateKey(keyPath); err == nil {
-					config.Auth = append(config.Auth, ssh.PublicKeys(key))
-					fmt.Fprintf(os.Stderr, "Debug: Added default key: %s\n", keyName)
-				}
-			}
-		}
-	}
-
-	// If no auth methods available, provide helpful error
-	if len(config.Auth) == 0 {
-		return nil, fmt.Errorf("no SSH authentication methods available - please set up SSH keys or SSH agent")
-	}
-
-	// Connect to the remote host
-	addr := net.JoinHostPort(host.Hostname, host.Port)
-	fmt.Fprintf(os.Stderr, "Debug: Connecting to %s\n", addr)
-	client, err := ssh.Dial("tcp", addr, config)
-	if err != nil {
-		return nil, fmt.Errorf("failed to connect to %s (%s): %w", host.Name, addr, err)
-	}
-
-	fmt.Fprintf(os.Stderr, "Debug: Successfully connected to %s\n", host.Name)
-	return client, nil
-}
-
-// sshAgentAuth returns SSH agent authentication method
-func sshAgentAuth() (ssh.AuthMethod, error) {
-	// Try to connect to SSH agent
-	agentConn, err := net.Dial("unix", os.Getenv("SSH_AUTH_SOCK"))
-	if err != nil {
-		return nil, err
-	}
-
-	sshAgent := agent.NewClient(agentConn)
-	return ssh.PublicKeysCallback(sshAgent.Signers), nil
-}
 
 // findAvailablePort finds an available local port
 func findAvailablePort() (int, error) {

ssh_config.go

@@ -175,11 +175,15 @@ func (sc *SSHConfig) GetHosts() []SSHHost {
 	return sc.Hosts
 }
 
-// GetHostByName returns a specific host by name
+// GetHostByName returns a specific host by name with expanded variables
 func (sc *SSHConfig) GetHostByName(name string) (*SSHHost, error) {
 	for _, host := range sc.Hosts {
 		if host.Name == name {
-			return &host, nil
+			// Return a copy with expanded shell variables
+			expandedHost := host
+			expandedHost.User = expandShellVars(host.User)
+			expandedHost.Identity = expandShellVars(host.Identity)
+			return &expandedHost, nil
 		}
 	}
 	return nil, fmt.Errorf("host '%s' not found", name)