We use this to check our puppet scripts as a git pre-commit hook.

Puppet syntax checking pre-commit hook

#!/opt/local/bin/php
<?php

// Git pre-commit file to check Puppet for errors

$files = array();
exec('git diff-index --cached --name-only HEAD', $files);

$exitcode = 0;

foreach($files as $file) {

  $output = '';

  if (!preg_match('/\.pp$/i', $file))
    continue;

  // file might be being removed
  if (!file_exists($file))
    continue;

  exec('puppet apply --parseonly '.escapeshellarg($file), $output, $return);

  if (!$return) // gives a 0 error code if everything went well
    continue;

  $exitcode = 1; // abort the commit
  
  echo "\n-------------- PUPPET PARSE ERRORS! ----------------\n";
  echo implode("\n", $output)."\n"; // an extra newline to make it look good
  echo "-------------- FIX BEFORE COMMIT ----------------\n\n";

}

exit($exitcode);