Added writing files, reading files, listing files, removing files.

I added a very simple writing, reading, listing and deleting file system. 
It writes everything to RAM in an array, so you really shouldn't go much overboard with this.
Commands are simple and are included in the main file. The arduino doesn't really need any other extention or anything, just upload the code and hacker away!

GrainOS.ino

@@ -1,33 +1,113 @@
+
+struct File {
+    String name;
+    String content;
+    bool used;
+};
+
+const int MAX_FILES = 10;  //file limit
+File files[MAX_FILES];     
+
+
+void clearScreen() {
+    for (int i = 0; i < 50; i++) {
+        Serial.println();         //function that clears your screen (again this is stupid)
+    }
+}
+
+
+void listFiles() {
+    Serial.println("Files:");
+    for (int i = 0; i < MAX_FILES; i++) {
+        if (files[i].used) {                    //FUNCTION THAT MAKES LS WORK
+            Serial.println("- " + files[i].name);
+        }
+    }
+}
+
+
+void writeFile(String name, String content) {
+    for (int i = 0; i < MAX_FILES; i++) {
+        if (!files[i].used) {  
+            files[i].name = name;               //function that writes to file
+            files[i].content = content;
+            files[i].used = true;
+            Serial.println("File written: " + name);
+            return;
+        }
+    }
+    Serial.println("Error: No space left in RAM!");
+}
+
+void readFile(String name) {
+    for (int i = 0; i < MAX_FILES; i++) {
+        if (files[i].used && files[i].name == name) {
+            Serial.println("Content of " + name + ": " + files[i].content); //function that reads written files
+            return;
+        }
+    }
+    Serial.println("Error: File not found!");
+}
+
+
+void deleteFile(String name) {
+    for (int i = 0; i < MAX_FILES; i++) {
+        if (files[i].used && files[i].name == name) {
+            files[i].used = false;  // Marks files as deleted
+            Serial.println("Deleted file: " + name);
+            return;
+        }
+    }
+    Serial.println("Error: File not found!"); // WAH WAH WAH 
+}
+
 void setup() {
-  Serial.begin(9600);
-  bool Userregistered = false;
+    Serial.begin(9600);
 }
 
 void loop() {
-  if (Serial.available()) {
-    String input = Serial.readStringUntil('\n'); 
-    input.trim();
+    if (Serial.available()) {
+        String input = Serial.readStringUntil('\n');
+        input.trim();
 
-    if (input == "clear") {
-      for (int i = 0; i < 50; i++) {
-        Serial.println(); // very, very, VERY scuffed clear command. Adds 50 blank likes to the 'terminal'
-      }
-    } 
-    else if (input.startsWith("echo")) {
-      String message = input.substring(5); //simple echo command (absolutely stolen from linux and made even more scuffed!)
-      message.trim(); 
-      
-      if (message.length() > 0) {
-        Serial.println(message); 
-      }
+        if (input == "clear") {
+            clearScreen(); //clears screen (very scuffed)
+        }
+        else if (input.startsWith("echo ")) {
+            String message = input.substring(5); // It's just echo with less functionality
+
+            message.trim();
+            Serial.println(message);
+        }
+        else if (input.startsWith("format(") && input.endsWith(")")) {
+            input = input.substring(7, input.length() - 1);
+            input.replace("\"", ""); //Formatting for Yasmina :)
+            input.replace(",", " ");
+            Serial.println(input);
+        }
+        else if (input.startsWith("write ")) {
+            int space = input.indexOf(' ', 6);
+            if (space != -1) {
+                String name = input.substring(6, space); // writes to files, I didn't know what to call this command so just write, fuck It
+                String content = input.substring(space + 1);
+                writeFile(name, content);
+            } else {
+                Serial.println("Usage: write <filename> <content>");
+            }
+        } 
+        else if (input.startsWith("read ")) {
+            String name = input.substring(5); // This is your cat, but this was simpler to write, fuck it
+            readFile(name);
+        } 
+        else if (input.startsWith("rm ")) {
+            String name = input.substring(7); //deletes files (has no flags)
+            deleteFile(name);
+        } 
+        else if (input == "ls") { //list files (currently directories don't exist (and let's be real probably won't))
+            listFiles();
+        } 
+        else {
+            Serial.println("Unknown command.");
+        }
     }
-    else if (input.startsWith("format(")) {
-      if (input.endsWith(")")) {
-        input = input.substring(7, input.length() - 1); 
-        input.replace("\"", ""); 
-        input.replace(",", " "); 
-        Serial.println(input); //Happy, Yasmina?
-      }
-    }
-  }
 }