example puppet unless for git changes

pull-changes.pp

exec { 'pull-changes':

    # This unless command makes it so this exec only runs when the branch is behind the head
    unless => [ 
      "/bin/bash -c 'cd /var/www/django/django \
      && CURRBRANCH=$(/usr/bin/git rev-parse --abbrev-ref HEAD)\
      && /usr/bin/git fetch origin \$CURRBRANCH \
      && /usr/bin/git rev-list HEAD...origin/\$CURRBRANCH --count'\
      | /bin/grep '0'" 
    ],

}