diff --git a/COOKBOOK.md b/COOKBOOK.md
index 269bf1ab..e100237a 100644
--- a/COOKBOOK.md
+++ b/COOKBOOK.md
@@ -8,6 +8,7 @@
     * [`require-root`](#require-root)
     * [`fast-finish`](#fast-finish)
     * [`lock-workdir`](#lock-workdir)
+    * [`unbuffer`](#unbuffer)
     * [`delay`](#delay)
     * [`command`](#command)
   * [Variables](#variables)
@@ -200,6 +201,25 @@ lock-workdir no
 
 <br/>
 
+#### `unbuffer`
+
+Disables I/O stream buffering.
+
+**Syntax:** `unbuffer <flag>`
+
+**Arguments:**
+
+* `flag` - Flag (_Boolean_) [`no` by default]
+
+**Example:**
+
+```yang
+unbuffer yes
+
+```
+
+<br/>
+
 #### `delay`
 
 Delay between commands.