Know the next available subnet
I have many Docker subnets and I need to know which one is the next available.
First I need to know all existing ones:
for N in $(docker network list --format "{{.Name}}"); do docker network inspect ${N} --format "{{(index .IPAM.Config 0).Subnet}} {{(index .IPAM.Config 0).Gateway}} {{.Name}}" 2>/dev/null ; done
Then I need to sort these in order to ease what is the next available slot:
(for N in $(docker network list --format "{{.Name}}"); do docker network inspect ${N} --format "{{(index .IPAM.Config 0).Subnet}} {{(index .IPAM.Config 0).Gateway}} {{.Name}}" 2>/dev/null ; done) | sort -t . -k 2,2n -k 3,3n -k 4,4n | grep -v '^$'