website: validate command docs

website/source/docs/command-line/validate.html.markdown

+---
+layout: "docs"
+---
+
+# Command-Line: Validate
+
+The `packer validate` command is used to validate the syntax and configuration
+of a [template](/docs/templates/introduction.html). The command will return
+a zero exit status on success, and a non-zero exit status on failure. Additionally,
+if a template doesn't validate, any error messages will be outputted.
+
+Example usage:
+
+```
+$ packer validate my-template.json
+Template validation failed. Errors are shown below.
+
+Errors validating build 'vmware'. 1 error(s) occurred:
+
+* Either a path or inline script must be specified.
+```
+
+## Options
+
+* `-syntax-only` - Only the syntax of the template is checked. The configuration
+  is not validated.

website/source/layouts/docs.erb

@@ -33,7 +33,7 @@
 							<li class="nav-header">Command-Line</li>
 							<li><a href="/docs/command-line/introduction.html">Introduction</a></li>
 							<li><a href="#">Build</a></li>
-							<li><a href="#">Validate</a></li>
+							<li><a href="/docs/command-line/validate.html">Validate</a></li>
 
 							<li class="nav-header">Templates</li>
 							<li><a href="/docs/templates/introduction.html">Introduction</a></li>