diff --git a/content/js/config/index.js b/content/js/config/index.js
index 1b41c82..a683915 100644
--- a/content/js/config/index.js
+++ b/content/js/config/index.js
@@ -54,3 +54,4 @@ const locations = {
         ]
     }
 }
+
diff --git a/content/js/shell/func.js b/content/js/shell/func.js
index 5e1a553..d5bf991 100644
--- a/content/js/shell/func.js
+++ b/content/js/shell/func.js
@@ -121,13 +121,21 @@ function su(cmd) {
         } else {
             root = true;
             let ret = 'Command not found';
+            let err = false;
 
             try {
                 ret = commands[cmd[0]]['func'](cmd.slice(1));
-            } catch {}
+            } catch (e) {
+                if (e.constructor !== TypeError) err = e;
+            }
 
             root = false;
 
+            if (err) {
+                alert(`ERROR (report it to 'cd src'): ${err}`);
+                throw err;
+            }
+
             return ret;
         }
     } else {
diff --git a/content/js/shell/index.js b/content/js/shell/index.js
index e07f1e8..2d52572 100644
--- a/content/js/shell/index.js
+++ b/content/js/shell/index.js
@@ -4,6 +4,16 @@ let cmd_history = document.getElementById('cmd_hist');
 let shell = document.getElementById('shell');
 var is_root = false;
 
+const html_bad_tags = {
+    '&': '&',
+    '<': '&lt;',
+    '>': '&gt;'
+};
+
+function replaceTag(tag) {
+    return html_bad_tags[tag] || tag;
+}
+
 function main() {
     cmd_prompt.onkeypress = (e) => {
         if (!cmd_prompt.value) return;
@@ -17,12 +27,12 @@ function main() {
 
             if (commands[command]) {
                 if (commands[command]['root_only'] && !root) {
-                    cmd_output.innerHTML = `'${command}' can <i>only</i> be ran as <b>root</b>. see <b>help su</b>`
+                    cmd_output.innerHTML = `'${command.replace(/[&<>]/g, replaceTag)}' can <i>only</i> be ran as <b>root</b>. see <b>help su</b>`
                 } else {
                     cmd_output.innerHTML = commands[command]['func'](argv);
                 } 
             } else {
-                cmd_output.innerHTML = `${command}: command not found`
+                cmd_output.innerText = `${command}: command not found`
             }