# Trigger Step

<%= toc %>

A *trigger* step starts a new build on a specified pipeline. Trigger steps can only be defined in your [pipeline.yml](/docs/pipelines/uploading-pipelines) file.

```yml
# This is the bare minimum. Defaults to HEAD / master
- trigger: "running-commands"
```

## Trigger step options

_Trigger steps can specify options for the new build:_

```yml
- trigger: "running-commands"
  label: "Trigger :pipeline: Party!"
  build:
    message: "Best build ever!"
    commit: "HEAD"
    branch: "master"
    meta_data:
      foo: "bar"
    env:
      MY_CUSTOM_ENV: "is great"
```

## Asynchronous triggers

_By default a trigger is synchronous and the new build is linked to the original build._

If you don't care about the result of the new build, this can be overridden:

```yml
- trigger: "running-commands"
  label: "Run the script (but I don't care)"
  async: true
  build:
    branch: "master"
```

Add documentation for trigger steps
Add documentation for trigger steps
