title: Cannot run `source` in AWS Codebuild
body: <p>I am using AWS CodeBuild along with Terraform for automated deployment of a Lambda based service. I have a very simple <code>buildscript.yml</code> that accomplishes the following:</p>
  
  <ul>
  <li>Get dependencies</li>
  <li>Run Tests</li>
  <li>Get AWS credentials and save to file (detailed below)</li>
  <li>Source the creds file</li>
  <li>Run Terraform</li>
  </ul>
  
  <p>The step "source the creds file" is where I am having my difficulty. I have a simply bash one-liner that grabs the AWS container creds off of <code>curl 169.254.170.2$AWS_CONTAINER_CREDENTIALS_RELATIVE_URI</code> and then saves them to a file in the following format:</p>
  
  <pre><code>export AWS_ACCESS_KEY_ID=SOMEACCESSKEY
  export AWS_SECRET_ACCESS_KEY=MYSECRETKEY
  export AWS_SESSION_TOKEN=MYSESSIONTOKEN
  </code></pre>
  
  <p>Of course, the obvious step is to simply <code>source</code> this file so that these variables can be added to my environment for Terraform to use. However, when I do <code>source /path/to/creds_file.txt</code>, CodeBuild returns: </p>
  
  <pre><code>[Container] 2017/06/28 18:28:26 Running command source /path/to/creds_file.txt
  /codebuild/output/tmp/script.sh: 4: /codebuild/output/tmp/script.sh: source: not found
  </code></pre>
  
  <p>I have tried to install <code>source</code> through <code>apt</code> but then I get an error saying that <code>source</code> cannot be found (yes, I've run <code>apt update</code> etc.). I am using a standard Ubuntu image with the Python 2.7 environment for CodeBuild. What can I do to either get Terraform working credentials for source this credentials file in Codebuild.</p>
  
  <p>Thanks!</p>