I needed to make a bash script for work that got the ip address of all new leases in the dhcp server, but only the new ones.
I spend some time looking for something useful, and therefore I decided to write a short post here to help others since i had a hard time finding it (maybe my google-fu is not as good as it should be)
The script had to do the following:
1. Get all new lines from a log file since last run
2. Get the ip addresses of the new leases
3. Do some stuff with the new ip addresses. This will not be part of this post
4. Run every minute in cron. This will also not be part of this post
In this post I will only cover how i did 1 and 2.