[SOLVED] Extract Key Value pairs which matches the regex in YAML using yq/sed/grep

Issue

I have this below YAML input and I am trying to extract shown output using yq

Input:

VAR-A: '{{a.b.VAR-A}}'
VAR-B: '{{a.b.VAR-B}}'
VAR-C: v0.0
VAR-D: '{{a.b.VAR-D}}-{{a.b.VAR-A}}'
VAR-E: '{{a.b.VAR-C}}-{{a.b.VAR-B}}-{{a.b.VAR-A}}'
VAR-F: '{{a.b.VAR-F}}'

Expected Output:

VAR-C: v0.0
VAR-D: '{{a.b.VAR-D}}-{{a.b.VAR-A}}'
VAR-E: '{{a.b.VAR-C}}-{{a.b.VAR-B}}-{{a.b.VAR-A}}'

My Attempt:

yq eval 'del( .[] | select (. == "{{a.b.*" ) )' abc.yaml

I am new to yq and any help will be much appreciated.

Based on @Inian's comment

**Note: I want to remove pairs where key name (VAR-A) in value {{a.b.VAR-A}} (after a.b.) matches and If I have more than {{a.b.VAR-A}} in values separated by - , I want to keep them

Solution

Is this what you expected ?

yq eval 'del(.[] | select(sub("^{{a\.b\.[^}]+}}$","")=="" ))' abc.yaml

The regex ^{{a\.b\.[^}]+}}$ matches a single {{...}} structure, because of ^ and $ at the beginning and end. [^}] means any character which is not }.

Then it substitute with empty string, if the result is again an empty string, it's selected for deletion.

If you just want to match {{a.b.VAR-A}}:

yq eval 'del(.[] | select(sub("^{{a\.b\.VAR-A}}$","")=="" ))' abc.yaml

Answered By - Philippe