diff --git a/README.md b/README.md
index 5ab4363..0e21ce4 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,7 @@ name as the package unless otherwise specified:
 - `coreutils`: multiple core commands including `cat`, `cp`, `echo`, `ls`, `mkdir`, `mv`, `rm`, `touch`, `uname`, and `wc`
 - `grep`
 - `lua`
+- `tree`
 - `vim`
 
 ## Build
diff --git a/demo/cockle-config-in.json b/demo/cockle-config-in.json
index 99dbd5e..ca4bf36 100644
--- a/demo/cockle-config-in.json
+++ b/demo/cockle-config-in.json
@@ -6,6 +6,9 @@
     "package": "local-cmd",
     "local_directory": "../test/local-packages"
   },
+  {
+    "package": "tree"
+  },
   {
     "package": "vim"
   }
diff --git a/demo/ui-tests/demo.test.ts b/demo/ui-tests/demo.test.ts
index 2d85f52..8336639 100644
--- a/demo/ui-tests/demo.test.ts
+++ b/demo/ui-tests/demo.test.ts
@@ -21,9 +21,6 @@ test('visual test', async ({ page }) => {
 
   await page.locator('div.xterm-screen').click(); // sets focus for keyboard input
 
-  await inputLine(page, 'ls'); // avoid timestamps
-  await page.waitForTimeout(wait);
-
   await inputLine(page, 'cp file.txt file2.txt');
   await page.waitForTimeout(wait);
 
diff --git a/demo/ui-tests/demo.test.ts-snapshots/visual-test-1-chromium-linux.png b/demo/ui-tests/demo.test.ts-snapshots/visual-test-1-chromium-linux.png
index 421f74e..522d92d 100644
Binary files a/demo/ui-tests/demo.test.ts-snapshots/visual-test-1-chromium-linux.png and b/demo/ui-tests/demo.test.ts-snapshots/visual-test-1-chromium-linux.png differ
diff --git a/src/buffered_io.ts b/src/buffered_io.ts
index d8d6ffe..159a3d1 100644
--- a/src/buffered_io.ts
+++ b/src/buffered_io.ts
@@ -65,6 +65,13 @@ abstract class BufferedIO {
     return this._enabled;
   }
 
+  utf8ArrayToString(chars: Int8Array): string {
+    if (this._utf8Decoder === undefined) {
+      this._utf8Decoder = new TextDecoder('utf8');
+    }
+    return this._utf8Decoder.decode(chars);
+  }
+
   protected _clear() {
     this._readArray[READ_MAIN] = 0;
     this._readArray[READ_WORKER] = 0;
@@ -92,6 +99,8 @@ abstract class BufferedIO {
 
   protected _maxWriteChars: number = 256; // Multiples of this can be sent consecutively.
   protected _writeArray: Int32Array;
+
+  private _utf8Decoder?: TextDecoder;
 }
 
 export namespace MainBufferedIO {
diff --git a/src/commands/wasm_command_runner.ts b/src/commands/wasm_command_runner.ts
index ae81fe7..a3a2ea9 100644
--- a/src/commands/wasm_command_runner.ts
+++ b/src/commands/wasm_command_runner.ts
@@ -74,7 +74,7 @@ export abstract class WasmCommandRunner implements ICommandRunner {
       }
 
       const chars = buffer.slice(offset, offset + length);
-      const text = String.fromCharCode(...chars);
+      const text = bufferedIO.utf8ArrayToString(chars);
       const isStderr = stream.path === '/dev/tty1';
 
       if (isStderr && cmdName === 'touch' && args.length > 1) {
diff --git a/test/cockle-config-in.json b/test/cockle-config-in.json
index 2405d5e..10a5b16 100644
--- a/test/cockle-config-in.json
+++ b/test/cockle-config-in.json
@@ -2,6 +2,9 @@
   {
     "package": "lua"
   },
+  {
+    "package": "tree"
+  },
   {
     "package": "vim"
   },
diff --git a/test/tests/command/tree.test.ts b/test/tests/command/tree.test.ts
new file mode 100644
index 0000000..24dc18b
--- /dev/null
+++ b/test/tests/command/tree.test.ts
@@ -0,0 +1,24 @@
+import { expect } from '@playwright/test';
+import { shellLineSimple, test } from '../utils';
+
+test.describe('tree command', () => {
+  test('should write version', async ({ page }) => {
+    const output = await shellLineSimple(page, 'tree --version');
+    expect(output).toMatch(
+      '\r\ntree v2.2.1 © 1996 - 2024 by Steve Baker, Thomas Moore, Francesc Rocher, Florian Sesser, Kyosuke Tokoro\r\n'
+    );
+  });
+
+  test('should write tree', async ({ page }) => {
+    const output = await shellLineSimple(page, 'tree');
+    expect(output).toMatch(
+      'tree\r\n' +
+        '.\r\n' +
+        '├── dirA\r\n' +
+        '├── file1\r\n' +
+        '└── file2\r\n' +
+        '\r\n' +
+        '2 directories, 2 files\r\n'
+    );
+  });
+});
diff --git a/test/tests/shell.test.ts b/test/tests/shell.test.ts
index d433e4f..d562bd6 100644
--- a/test/tests/shell.test.ts
+++ b/test/tests/shell.test.ts
@@ -157,6 +157,11 @@ test.describe('Shell', () => {
       expect(output[14]).toMatch(/Error: cd: too many arguments/);
       expect(output[15]).toMatch('\r\n?=1\r\n');
     });
+
+    test('should support unicode', async ({ page }) => {
+      const output = await shellLineSimple(page, 'echo 🚀');
+      expect(output).toMatch(/^echo 🚀\r\n🚀\r\n/);
+    });
   });
 
   test.describe('echo input', () => {
@@ -207,8 +212,8 @@ test.describe('Shell', () => {
         const ret1 = output.textAndClear();
         return [ret0, ret1];
       });
-      expect(output[0]).toMatch(/^t\r\ntail\r\ntouch\r\ntr\r\ntty\r\n/);
-      expect(output[1]).toMatch(/^\r\ntail {3}tr\r\ntouch {2}tty\r\n/);
+      expect(output[0]).toMatch(/^t\r\ntail\r\ntouch\r\ntr\r\ntree\r\ntty\r\n/);
+      expect(output[1]).toMatch(/^\r\ntail {3}tree\r\ntouch {2}tty\r\ntr\r\n/);
     });
 
     test('should add common startsWith', async ({ page }) => {