I have a question. I would like to check when the raspi system starts or if the serial cpu is correct. If not, he would be rebooting. So he would be doing reboot loops all the time. I found the command to check the serial cpu command:

cat /proc/cpuinfo | grep Serial | cut -d ' ' -f 2

How to compare the result of this command to the value of eg 000000ddd0d0d?? And I do not know how to look like such a check script and where to put it in the Ubuntu system (/etc/init.d/rc.local ??).

Thank you for your help Sorry for my English. It is correctly??:

STR=cat /proc/cpuinfo | grep Serial | cut -d ' ' -f 2
if $STR != '000000ddd0d0d'; then
  • Is this an attempt to lock down your software to a particular hardware? If so, see here and here why it's not gonna work. rc.local is especially easy to break since it can be easily bypassed at boot. Commented Oct 19, 2018 at 8:45

1 Answer 1


For a shell script comparison, you may wanna peruse this Other Comparison Operators. Also, you can probably achieve this with a case statement as shown below. I have tested the scripts on my Rpi0 and it works.

STR=$(cat /proc/cpuinfo | grep Serial | cut -d ' ' -f 2)
case $STR in
 000000ddd0d0d) reboot;;
 default) echo "Unknown CPU ID of $STR";;

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