Cannot run a script after reboot using Cron

Question

I'm trying to start a script containing cgminer for mining when the raspberry pi reboots however it doesn't.

My crontab contains the following.

@reboot sleep 120 && sudo /home/pi/StartVPN.sh
@reboot sleep 120 && /home/pi/Run_Miner_SHA256.sh
0 6 * * * sudo shutdown -r

@reboot sleep 120 && sudo /home/pi/StartVPN.sh => Runs perfectly after 2 minutes my VPN is connected with the server.

@reboot sleep 120 && /home/pi/Run_Miner_SHA256.sh => Never runs and I must run it manually.

0 6 * * * sudo shutdown -r => Works fine and the raspberry pi reboots at 6 AM.

My "Run_Miner_SHA256.sh" file contains the following:

cd /home/pi/mining/newpac/cgminer && sudo nohup ./cgminer -o stratum+tcp://192.168.100.100:3256 -u 75ZNRZpEqYBM72GwGi6LCjaKM5Ao715ijD -p anything --gekko-newpac-freq 40  >/dev/null 2>&1 &

What I'm missing here?

Answer 1

add the following line above your line

TERM=xterm

Answer 2

for debugging purposes remove the >/dev/null 2>&1 & and redirect it to a log file

BTW why do you need the nohup and the & at the end ?

Answer 3

Two things:

First Thing:

WRT your error: You need to remember that cron jobs do not run under the same environment as your interactive shell. You can see this by running printenv in a cron job, and then comparing the output to same command executed from your command line (interactive shell); i.e.

@reboot printenv > /home/pi/mycronlog.txt 2>&1 

and then from the command line:

$ printenv

As you'll see, there are substantial differences! Also note that cron defaults to sh (not bash), and that may not work for all the commands in your script.

I won't try to debug your code, but I will make some observations based on a quick look:

• it's certain that if you either change your cron environment, or respect the current environment (e.g. by using full path statements instead of ./), it will run.

• there is no point using nohup in a cron job (REF). Read man nohup

• ./ should be a specific path; e.g. /home/pi

• Have you tried something perhaps less convoluted?; e.g. instead of:

  @reboot sleep 120 && /home/pi/Run_Miner_SHA256.sh 
  

  perhaps try something like this:

  @reboot sleep 120; /home/pi/mining/newpac/cgminer  -o stratum+tcp://192.168.100.100:3256 -u 75ZNRZpEqYBM72GwGi6LCjaKM5Ao715ijD -p anything --gekko-newpac-freq 40 >/dev/null 2>&1
  

  NOTE: There are several things left unclear from your question; for example, why send all output to /dev/null?, is cgiminer a folder name and the name of an executable file? (cgiminer/cgiminer - or cgiminer?)

Second Thing:

Using sudo in your cron jobs works in RPi OS, but it will fail in most distros, and is not "best practice". If you need elevated privileges in a cron job, you should run under the root crontab:

$ sudo crontab -e 

When running in the root crontab, you don't need sudo at all.