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So, basically I am using wiringPI library and its sample code for ds1302 chip. It works great by the way - writing and reading to and from ds1302 chip is a breeze. I can initiate PI's date and time update with ds1302 date and time and vice versa. I want to automate this process for boot-time and periodic update of ds1302 chip with PI's date and time. I got the boot-time PI's date and time update from ds1302 date and time by calling a script at boot.

For periodic update of ds1302 date time from PI's date time, I am using sudo crontab -e The script itself is working as expected but not updating my ds1302 chip's date time. In the crontab, I have the following.

* * * * * date>>/home/pi/script/cron.txt
* * * * * sudo ./home/pi/script/ds1302 -sdsc

I know crontab is working, because I do see cron.txt with time stamp for every minute, but the ds1302 chip date time has not updated to the PI's date time. The weird thing is that if I were to execute the command, sudo ./home/pi/script/ds1302 -sdsc on the terminal, it WORKS instantly. So, why won't crontab run the command or having difficulty running the command?

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    This is a duplicate. You have been told before to use absolute paths in crontab. Anything starting with a . is not an absolute path.
    – joan
    Commented Jun 21, 2016 at 19:25
  • @joan The reason I have . in the beginning is to execute ds1302 program. dot followed by absolute path /home/pi/script/.
    – ThN
    Commented Jun 21, 2016 at 19:27
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    You have changed an absolute path to a relative path. Get rid of the dot.
    – joan
    Commented Jun 21, 2016 at 19:28
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    You need to look online for a Linux tutorial to explain such things as absolute and relative paths.
    – joan
    Commented Jun 21, 2016 at 19:36
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    You really need to look through a Linux tutorial. It will cover many similar things to this which will catch you out until you understand what is going on.
    – joan
    Commented Jun 21, 2016 at 19:55

1 Answer 1

Reset to default
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Just remove the dot

* * * * * sudo /home/pi/script/ds1302 -sdsc

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    You have answered your own question based on @joan comments which is a bit cheeky - you could have at least mentioned here help/comments. Second you have not explained what the removing the dot does and why it worked - this would show you understood the problem and solution not just repeated the advice you were given.
    – Steve Robillard
    Commented Jun 21, 2016 at 20:00

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