Add a cron job in a command line
As you familiar with UNIX cron with crontab -e when you going to add a new schedule cron job.. do you ever tried to add a cron job up to 100 machine?
Simply to use pipe-in with crontab -l to regenerate the crontab.
Here you are
(crontab -l; echo "0 0 * * * /path/to/myscript.sh") | crontab -
Easy?!