How to make a Linux powered garden sprinkler system.

Step 6 Scheduling...

Crontab is a very easy and powerful way to schedule tasks in linux. You can use it to run any program at a predetermined time daily monthly hourly down to the second. I have mine set to be on for 5 min and off for 5 min.

Note. You must run the parcon executable as root. This means you must edit the root user's crontab file.

1. sudo su
2. enter password
3. crontab -e

Here is an example of my crontab file.

# m h  dom mon dow   command
30 7 * * 1,3,5 /usr/bin/parcon 1h 2h 3h 4h 5h 6h 7h 8h
35 7 * * 1,3,5 /usr/bin/parcon 1l 2l 3l 4l 5l 6l 7l 8l

40 7 * * 1,3,5 /usr/bin/parcon 1h 2h 3h 4h 5h 6h 7h 8h
45 7 * * 1,3,5 /usr/bin/parcon 1l 2l 3l 4l 5l 6l 7l 8l

50 7 * * 1,3,5 /usr/bin/parcon 1h 2h 3h 4h 5h 6h 7h 8h
55 7 * * 1,3,5 /usr/bin/parcon 1l 2l 3l 4l 5l 6l 7l 8l

00 8 * * 1,3,5 /usr/bin/parcon 1h 2h 3h 4h 5h 6h 7h 8h
05 8 * * 1,3,5 /usr/bin/parcon 1l 2l 3l 4l 5l 6l 7l 8l

10 8 * * 1,3,5 /usr/bin/parcon 1h 2h 3h 4h 5h 6h 7h 8h
15 8 * * 1,3,5 /usr/bin/parcon 1l 2l 3l 4l 5l 6l 7l 8l

20 8 * * 1,3,5 /usr/bin/parcon 1h 2h 3h 4h 5h 6h 7h 8h
25 8 * * 1,3,5 /usr/bin/parcon 1l 2l 3l 4l 5l 6l 7l 8l
 

Comments

[jinchuuriki]

What programming language is this? I do not know anything about it.

[dcathey]

It's crontab entries (see /etc/crontab or files in /etc/cron.d) for further examples. The comment "# m h dom mon dow command" provides the basic format:
m - minute after the hour
h - hour of the day
dom - day of month
mon - month of year
dow - day of week (0=sunday)
command - shell command to execute

So the first entry will execute "/usr/bin/parcon 1h 2h 3h 4h 5h 6h 7h 8h" at 7:30 every monday, wednesday, and friday