Dns

A team member reported a problem with pre-commit hook I wrote, check-dns-serial, which ensures the SOA serial number is updated on any modified zone files. The script was giving them an error when they made a commit after the 8th revision in a day. It was an interesting bug in a bash script that I thought might be helpful to share. The serial number is, by convention, stored as a date string plus a 2-digit revision number. For example, 2021090104 would be today’s 4th change. This allows for 99 changes a day. The script splits this string (using cut) into two variables, the date and the revision. At one point, it checks to see if the old revision is already 99, to avoid an overflow. This is line that threw the error: ...