The Crontab is the way we control what programs we want to run in the background.

Here is a link on how it works: Crontab.guru – The cron schedule expression editor

We are going to add the following lines to the crontab:

• */3 * * * * python /home/aranet/getAranetData.py (MAC address) > /home/aranet/aranet.txt
  */1 * * * * python /aranet/coPng.py > /home/aranet/coPng.log
  1 1 * * * python /home/aranet/clean_data_folder.py > /home/pi/clean.log

You now will need to use the Linux editor nano or vi.  nano is more user friendly

in the /home/aranet directory type crontab -e (this will only come up the first time you run crontab -e)

you will see:

Select an editor. To change later, run ‘select-editor’.
1. /bin/nano <—- easiest
2. /usr/bin/vim.tiny
3. /bin/ed

if using nano type 1

You now will see

# 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 the month (dom), month (mon),
# and day of the 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

Now just add the above to  the bottom of the file:

now save the file

to verify that all is well-run crontab -l (that is a little L, which stands for a list, a -e stans for edit)

notice the 1 1 * * * in the last line.  That means it will run every day, 1 minute after 1 AM.

The others will run every minute. if you want to run every 2 minutes, then It would be */2 * * * *

 

Next, display data via a web page