I wonder why my cron job didn't work. Our team consider that the cron job didn't work because we didn't properly update the crontab file. Following is the process what we did:
Backup the current cron jobs.
cd /var/spool/spool/cron/crontabs cp -p jeus jeus.20170120
Remove all the cron jobs for the user, whose name is jeus.
crontab -r
Make sure if all the cron jobs are removed.
crontab -l
After about 12 hours, we recover it like this.
cd /var/spool/spool/cron/crontabs cp -p jeus.20170120 jeus
We think that our cron jobs didn't work because we didn't update the crontab file like the following commands. We just recovered the file we saved before.
1. Open (crontab -e)
2. Save (:wq)
Do you think our idea is reasonable? Do you have any ideas on the issue we had experience?
(Update) The problem is that cron jobs weren't executed at all.