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Scheduling commands

It is possible to schedule commands that execute at a given interval, e.g. each minute. To do so, you can use crontab.

How to add a scheduled command

You just have to edit the crontab -e file with sudo:

sudo crontab -e

Each line of the file define a time of execution and the command to run. The time is composed of 5 numbers, which respectively stand for:

  1. Minute
  2. Hour
  3. Day of month
  4. Month
  5. Day of week

It is possible to use * in any of these fields, which stands for "any". Using * * * * * will mean that the script will be launched every minute.

List of implemented scheduled commands

On the submitter

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# Edit this file to introduce tasks to be run by cron.
# 
# Each task to run has to be defined through a single line
# indicating with different fields when the task will be run
# and what command to run for the task
# 
# To define the time you can provide concrete values for
# minute (m), hour (h), day of month (dom), month (mon),
# and day of week (dow) or use '*' in these fields (for 'any').
# 
# Notice that tasks will be started based on the cron's system
# daemon's notion of time and timezones.
# 
# Output of the crontab jobs (including errors) is sent through
# email to the user the crontab file belongs to (unless redirected).
# 
# For example, you can run a backup of all your user accounts
# at 5 a.m every week with:
# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
# 
# For more information see the manual pages of crontab(5) and cron(8)
# 
# m h  dom mon dow   command

* * * * * /home/guest/bin/docker_kill_old >> /var/log/docker_kill_old.log 2>&1