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cron_automation

Cron Automation

2016


This information comes from “https://help.ubuntu.com/community/CronHowto

To edit the cron job list:

  crontab -e (don't sudo, or you will change root cron, not your user cron)


Then add your job, which has the format:
Each line has five time-and-date fields, followed by a command, followed by a newline character ('\n'). The fields are separated by spaces. The five time-and-date fields cannot contain spaces. The five time-and-date fields are as follows: minute (0-59), hour (0-23, 0 = midnight), day (1-31), month (1-12), weekday (0-6, 0 = Sunday).

  01 04 1 1 1 /usr/bin/somedirectory/somecommand\\ 


The above example will run /usr/bin/somedirectory/somecommand at 4:01am on January 1st plus every Monday in January.

An asterisk (*) can be used so that every instance (every hour, every weekday, every month, etc.) of a time period is used.

  01 04 * * * /usr/bin/somedirectory/somecommand



Working Example


This example will run the script pibackup at 3am every Sunday

  00 03 0 0 0 /mnt/usbstorage/backups/scripts/pibackup


Check if Cron is Running


  /etc/init.d/cron status
  
  ● cron.service - Regular background program processing daemon
    Loaded: loaded (/lib/systemd/system/cron.service; enabled)
    Active: active (running) since Wed 2016-08-03 20:37:22 BST; 19h ago
    Docs: man:cron(8)
    Main PID: 453 (cron)
        CGroup: /system.slice/cron.service
            └─453 /usr/sbin/cron -f



Check Jobs


  crontab -lu pi
  
  Shows current cron jobs for user pi



cron_automation.txt · Last modified: 2017/02/28 18:00 (external edit)