[FEATURE] systeminfo

Fixes #82

Author: nihaltp

CheckList.md

@@ -7,7 +7,7 @@
 ---
 
 ## 🧭 System Information & Management
-- [ ] systeminfo  
+- [x] systeminfo  
 - [x] hostname  
 - [x] ver  
 - [ ] vol  

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

@@ -106,7 +106,6 @@ private static void registerCommands(Map<String, Command> commands) {
         commands.put("unalias", new UnaliasCommand());
         commands.put("rename", new RenameCommand());
         commands.put("set", new SetCommand());
-          }
+        commands.put("systeminfo", new SysteminfoCommand());
+    }
 }
-
-        

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

@@ -0,0 +1,74 @@
+package com.mycmd.commands;
+
+import com.mycmd.Command;
+import com.mycmd.ShellContext;
+import java.lang.management.ManagementFactory;
+import java.lang.management.OperatingSystemMXBean;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.text.NumberFormat;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.TimeZone;
+
+public class SysteminfoCommand implements Command {
+    @Override
+    public void execute(String[] args, ShellContext context) {
+        OperatingSystemMXBean osBean = ManagementFactory.getOperatingSystemMXBean();
+        NumberFormat nf = NumberFormat.getInstance();
+        Runtime rt = Runtime.getRuntime();
+        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+        sdf.setTimeZone(TimeZone.getDefault());
+
+        String hostname;
+        try {
+            hostname = InetAddress.getLocalHost().getHostName();
+        } catch (UnknownHostException e) {
+            hostname = System.getenv("COMPUTERNAME");
+            if (hostname == null) hostname = System.getenv("HOSTNAME");
+            if (hostname == null) hostname = "Unknown";
+        }
+
+        long uptime = ManagementFactory.getRuntimeMXBean().getUptime();
+        long bootTimeMillis = System.currentTimeMillis() - uptime;
+        long maxMem = rt.maxMemory();
+        long totalMem = rt.totalMemory();
+        long freeMem = rt.freeMemory();
+        long usedMem = totalMem - freeMem;
+
+        System.out.println();
+        System.out.println("Host Name:             " + hostname);
+        System.out.println("OS Name:               " + System.getProperty("os.name"));
+        System.out.println("OS Version:            " + System.getProperty("os.version"));
+        System.out.println("Architecture:          " + System.getProperty("os.arch"));
+        System.out.println("User Name:             " + System.getProperty("user.name"));
+        System.out.println("Java Vendor:           " + System.getProperty("java.vendor"));
+        System.out.println("Java VM:               " + System.getProperty("java.vm.name"));
+        System.out.println("Available Processors:  " + osBean.getAvailableProcessors());
+        System.out.println("JVM Boot Time:         " + sdf.format(new Date(bootTimeMillis)));
+        System.out.println("User Language:         " + System.getProperty("user.language"));
+        System.out.println("User Country:          " + System.getProperty("user.country"));
+        System.out.println("Home Directory:        " + System.getProperty("user.home"));
+        System.out.println();
+        System.out.println("JVM Memory (Heap):");
+        System.out.println("  Total: " + nf.format(totalMem / (1024 * 1024)) + " MB");
+        System.out.println("  Used:  " + nf.format(usedMem / (1024 * 1024)) + " MB");
+        System.out.println("  Free:  " + nf.format(freeMem / (1024 * 1024)) + " MB");
+        System.out.println(
+                "  Max:   "
+                        + (maxMem == Long.MAX_VALUE
+                                ? "No Limit"
+                                : nf.format(maxMem / (1024 * 1024)) + " MB"));
+        System.out.println();
+    }
+
+    @Override
+    public String description() {
+        return "Displays system and JVM information.";
+    }
+
+    @Override
+    public String usage() {
+        return "systeminfo";
+    }
+}