比较简单，这样就可以了

cat > /var/spool/cron/root <<EOF
* * * * * /usr/sbin/ntpdate cn.pool.ntp.org >> /var/log/ntpdate.log
EOF

?

?

?

项目中的应用：

config.sh

---------------------------------------------------

crontabfile=/var/spool/cron/mysql
if [ -e $crontabfile ]; then
echo "*/10 * * * * /home/mysql/PEnterAccount/DaemonPEnterAccount.sh" >>$crontabfile
else
touch $crontabfile
echo "*/10 * * * * /home/mysql/PEnterAccount/DaemonPEnterAccount.sh" >>$crontabfile
fi
service crond restart