mod: copy stderr from ssh session to locally running processes stderr

Log the `serve` version in the beginning with a closing log message.

internal/serve/serve.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io"
 	"net"
 	"os"
 	"os/signal"
@@ -59,6 +60,7 @@ func setupSshServer(host string, port string, host_key_path string, users map[st
 					if err := cmd.Run(); err != nil {
 						wish.Fatalln(s, err)
 					}
+					io.Copy(os.Stderr, s.Stderr())
 					next(s)
 				}
 			},
@@ -71,6 +73,9 @@ func setupSshServer(host string, port string, host_key_path string, users map[st
 // Serve an ssh application using the provided arguments.
 func Serve(host string, port string, host_key_path string, users map[string]string, name string, args []string) {
 	setupLogging()
+	log.Info("Running Serve (v2.7)...") // TODO make version string automatically the git tag (otherwise commit-hash)?
+	defer log.Info("Stopping Serve...")
+
 	srv, err := setupSshServer(host, port, host_key_path, users, name, args)
 	if err != nil {
 		log.Error("Could not start server", "error", err)