feature: IpConfig command implemented and tested

src/main/java/com/mycmd/App.java

@@ -99,6 +99,7 @@ private static void registerCommands(Map<String, Command> commands) {
         commands.put("pwd", new PwdCommand());
         commands.put("uptime", new UptimeCommand());
         commands.put("clearhistory", new ClearHistoryCommand());
+        commands.put("ipconfig", new IpConfig());
         commands.put("alias", new AliasCommand());
         commands.put("unalias", new UnaliasCommand());
     }

src/main/java/com/mycmd/commands/IpConfig.java

@@ -0,0 +1,46 @@
+package com.mycmd.commands;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.net.SocketException;
+import java.util.Enumeration;
+import com.mycmd.Command;
+import com.mycmd.ShellContext;
+
+/**
+ * Implements the "ipconfig" command for MyCMD.
+ */
+public class IpConfig implements Command {
+
+    @Override
+    public void execute(String[] args, ShellContext context) throws IOException {
+        try {
+            Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
+            while (interfaces.hasMoreElements()) {
+                NetworkInterface ni = interfaces.nextElement();
+                System.out.println("Interface: " + ni.getDisplayName());
+
+                Enumeration<InetAddress> addresses = ni.getInetAddresses();
+                while (addresses.hasMoreElements()) {
+                    InetAddress addr = addresses.nextElement();
+                    System.out.println("  IP Address: " + addr.getHostAddress());
+                }
+
+                System.out.println(); // blank line between interfaces
+            }
+        } catch (SocketException e) {
+            throw new IOException("Failed to get network interfaces", e);
+        }
+    }
+
+    @Override
+    public String description() {
+        return "Displays all network interfaces and their IP addresses";
+    }
+
+    @Override
+    public String usage() {
+        return "ipconfig";
+    }
+}