added some useless shell commands

kernel/kbd.c

@@ -79,6 +79,8 @@ void kbd_wait() {
     }
 }
 
-char kbd_read() {
-    return kbd_pop();
+uint32_t kbd_read(struct vfs_node* node, uint32_t offset, uint32_t size, uint8_t* buffer) {
+    if (!kbd_ready()) return -1;
+    buffer[0] = kbd_pop();
+    return 1;
 }