a、crontab -e,添加如下内容:
*/1 * * * * sh && echo "dd" >> /logs/cron-cc.log
*/1 * * * * sleep 30 && echo "cc" >> /logs/cron-cc.log
b、重启crond
systemctl reload crond
systemctl restart crond
service crond reload
c、查看当前用户定时任务
crontab -l
d、通过日志查看是否生效
tail -f /logs/cron-cc.log