add command to add keys to database

main.go

@@ -1,7 +1,54 @@
 package main
 
-import "fmt"
+import (
+	"flag"
+	"fmt"
+	"os"
+)
 
 func main() {
-	fmt.Println("gosh init")
+	flag.Usage = func() {
+		fmt.Fprintf(os.Stderr, "Usage: %s [gosh-flags] [user@host] [ssh-flags]\n", os.Args[0])
+		fmt.Fprintf(os.Stderr, "\nManagement Commands:\n")
+		fmt.Fprintf(os.Stderr, "  %s [flags] add-key <user_pattern> <host_pattern> <path_to_key>\n", os.Args[0])
+		fmt.Fprintf(os.Stderr, "\nFlags:\n")
+		flag.PrintDefaults()
+	}
+
+	dbPath := flag.String("db", "", "Path to the keys database (optional)")
+	flag.Parse()
+
+	args := flag.Args()
+	argc := len(args)
+
+	if argc == 0 {
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	cmd := args[0]
+
+	if cmd == "add-key" {
+		if argc != 4 {
+			fmt.Println("Error: Incorrect arguments for add-key.")
+			fmt.Println("Try: gosh [--db path] add-key <user_pattern> <host_pattern> <path_to_key>")
+			os.Exit(1)
+		}
+
+		db, err := initDB(*dbPath)
+		if err != nil {
+			fmt.Println("Error:", err)
+			os.Exit(1)
+		}
+
+		userPattern := args[1]
+		hostPattern := args[2]
+		keyPath := args[3]
+		err = addKey(db, userPattern, hostPattern, keyPath)
+		if err != nil {
+			fmt.Println("Error:", err)
+			os.Exit(1)
+		}
+		return
+	}
 }