Cron file location

/etc/
├── cron.d/hoge_cron

Setting of authority

sudo chmod 644 hoge_cron
sudo chown root:root hoge_cron

Command

crontab

options

-l # List cron
-e # Start the editor to set up cron
-u # Specify the user to set up cron
-r # Erase all cron settings

Cron Sample

SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root

# For details see man 4 crontabs

# Example of job definition:
# .---------------- minute (0 - 59)
# |  .------------- hour (0 - 23)
# |  |  .---------- day of month (1 - 31)
# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# |  |  |  |  |
# *  *  *  *  * user-name  command to be executed

Cron restert

sudo service crond restart

// centos7
sudo systemctl restart crond.service

Cron status confirmation

sudo service crond status

// centos7
sudo systemctl status crond.service

Cron log confirmation

sudo less /var/log/cron

// watch
sudo tail -f /var/log/cron