Hello Pi users,
After investing much time then expected to run a cron job at reboot in Rapbian. finally I am able to run the cron job at startup and able to execute the necessary commands at start-up.
It is quite Obvious that @reboot will run the cron job at start up but in Raspbian and Debian (wheezy) it is not the case.
@reboot does not works as expected and it is a bug in debaian you can read it here https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=635473
So here are the steps to for running cron job at reboot :-
log in to your pi using ssh
switch to root user using sudo bash
run the command crontab -e
put your command as @reboot bash /path/to/file/run.sh save it and get back on terminal
then start cron service by running /etc/init.d/cron start
then one additional step is to edit the /etc/rc.local file and add the following line in /etc/init.d/cron/start be sure that it should before exit 0.
now reboot your system by command reboot
and now your cron job is started you can check it by command ps aux | grep cron
also you can check the log tail /var/log/syslog.