anchor.diff:  build.branch =~ /.+\/release-123/
   ```
   
  -To run only when the build's tag begins with a `v` and ends with a `.0`, such as `v1.0`:
  +To run only when building a tag:
  +
  +```js
  +build.tag != null
  +```
  +
  +To run only when building a tag beginning with a `v` and ends with a `.0`, such as `v1.0`:
   
   ```js
   build.tag =~ /v[0-9]+\.0/
   ```
   
  -To run only when building a tag:
  -
  -```js
  -build.tag != null
  -```
  -
   To run only if the message contains `[skip tests]`, case insensitive:
   
   ```js
  
positive.code:  			<td><code>true false</code></td>
   		</tr>
   		<tr>
   			<td>Parentheses</td>
   			<td><code>( )</code></td>
   		</tr>
  
negative.code: 
  Use the `if` attribute in your pipeline's YAML to conditionally run a step.
  
  In the below example, the `tests` step will only be run if the build message does not contain the string "skip tests".
  
  ```yml
  steps:
  	- command: ./scripts/tests.sh
  	  label: tests
  	  if: build.message != "skip tests"
  ```
  
  The `if` attribute can be used in any type of step, and with any of the supported expressions and parameters. However, it cannot be used at the same time as the `branches` attribute.
  
  Multi-line conditionals can be added with the `|` character:
  
  