i saw in lot of ubuntu conf files that is containing include files. so, i think about that how to solve problem of many people that have dynamic ip address. so this question is based on that, to create network conf file with current ip address that is gonna be simply included imnstead of ip address, and than when ip address changes, to not need to open every single file with network configurations and change that ip, just simply by running comand:
echo xxx.xxx.xxx.xxx > ip.addr.conf
that can save lot of people using dhcp for ervers, also from complicated configurations, and save configuring time by running just one line of code.
my question is, how to make includes in generaly in conf files?