Adjust netplan yaml with sed or awk [duplicate] - bash

Question

This question already has answers here:
How can I parse a YAML file from a Linux shell script?
(23 answers)
Closed 26 days ago.
Here is our yaml:
network:
ethernets:
ens160:
addresses:
- 10.200.2.11/22
gateway4: 10.200.0.1
nameservers:
addresses:
- 8.8.8.8
- 4.4.4.4
search:
- cybertax.live
version: 2
I want to change the dns severs only.
From:
- 8.8.8.8
- 4.4.4.4
to:
- 10.10.10.10
- 10.10.10.11
How can I do this? Note: we cannot use or install yq so this needs to be done through sed or awk. Also, yes I know, this is not recommended, but its what needs to be done right now.
What I have tried so far:
sed -i '/ addresses:/,/ search:/ s/^/# /' $netplan_yaml
sed -i '/ nameservers:/a\ \ \ \ \ \ \ \ addresses:' $netplan_yaml
for i in ${!asar_dns[#]}; do
sed -i "/ addresses:/a\ \ \ \ \ \ \ \ - ${asar_dns[$i]}" $netplan_yaml
done
But this does three things wrong (that I can see).
It matches between addresses and search including the line wiht addresses and search. I only want what is AFTER addresses, and BEFORE search.
It puts the DNS addresses in the associative array between the older addresses that is commented out anywhere there is an "addresses". I dont want to do that on the commented out line.
i dont like how I have to use \ \ \ \ \ \ would much rather use a .* if possible but also need to use the addresses in the associative array.

Answer 1

I found a very hacky solution but it works. Open for feedback.
netplan_yaml=/etc/netplan/00-installer-config.yaml
baddns="$(sed -n '/.*nameservers:/,/.*search:/p' /etc/netplan/00-installer-config.yaml | grep -v 'nameservers\|addresses' | grep -v 'search' | grep -v 10.200 | awk '{print$2}')"
mapfile -t arr_baddns <<<$baddns
for i in ${arr_baddns[#]}; do
sed -i "/ - $i/s/^/#/g" $netplan_yaml
done
for i in ${!asar_dns[#]}; do
sed -i "/ addresses:/a\ \ \ \ \ \ \ \ - ${asar_dns[$i]}" $netplan_yaml
done

Answer 2

If ed is available/acceptable, with your given input.
Something like.
ed -s file.yaml <<-'EOF'
g/nameservers:/;/addresses:/;/search:/-s/[[:digit:].]\{1,\}/10.10.10.11/\
-s/[[:digit:].]\{1,\}/10.10.10.10/
,p
Q
EOF
Using variables for the values, something like:
#!/bin/sh
dns1=10.10.10.10
dns2=10.10.10.11
ed -s file.yaml <<-EOF
g/nameservers:/;/addresses:/;/search:/-s/[[:digit:].]\{1,\}/$dns2/\\
-s/[[:digit:].]\{1,\}/$dns1/
,p
Q
EOF
Change Q to w if in-place editing is required, ala sed -i
Remove the ,p to silence the output.