Update crontab from command line

I occasionally need to update the cron on a TON of hosts, and don't want to run crontab -e a TON of times..

crontab -l | grep 'chmod 666'

== Add an entry to an existing crontab ==
if [ $? -ne 0 ]
then
  cat <(crontab -l) <(echo "* * * * * chmod 666 /u01/core/*") | crontab -
  echo "NOTE: cron updated"
else
  echo "NOTE: cron was already updated"
fi

== Remove something from a crontab
[root@dvgllpsmsapp13 ~]# crontab -l
# Chmod something
0 0 * * * chmod 777 /tmp/test
0 0 * * * chown 777 /tmp/test
[root@dvgllpsmsapp13 ~]# cat <(crontab -l | grep -vi chmod) | crontab -
[root@dvgllpsmsapp13 ~]# crontab -l
0 0 * * * chown 777 /tmp/test
[root@dvgllpsmsapp13 ~]#