# Script to update DKIM entry in BIND zone file

This script takes two arguments:
 1. a BIND DNS zone file
 2. a DNS record generated by 'opendkim-genkey'

`opendkim-genkey` is part of the `opendkim-tools` Debian package

This script use regex to
1. extract the DKIM selector and the value of the TXT record from the DKIM TXT record generated by opendkim-genkey
2. replace the DKIM selector and TXT value in the zone file with the new values


## Example

- generate a new DKIM key for mail.example.org
- remember to increase the increment if generating a new key on the same date
```bash
INCREMENT=1; /usr/sbin/opendkim-genkey -b 2048 -d mail -s $(/bin/date +%Y%m%d)-$INCREMENT

# generate a DNS DKIM TXT record such as '20210811-1.txt'
/usr/sbin/opendkim-genkey -b 2048 -d example.org -s $(/bin/date +%Y%m%d)-1
```
Then run this update-dkim.py, passing the zone file you want to update and the above .txt file:
```bash
update-dkim.py <zone file> 20210811-1.txt
```
```sh
```