title: How to check cron syntax by script like "crontab -e" does?
body: <p>Let´s say i write cron files via script and modify them direct under 
  <code>/var/spool/cron/crontabs/</code>. When using the command <code>crontab -e</code> crontab checks the syntax when i exit the editor. Is there any way, to do the same check via script?</p>