yq v4 tools

Few operators :

1. Length

   We can get the length of an array using this length operator

    apple:
      - test: "eat"
      - test: "cut"
   

   Then the following command gives us the length

    length=$(yq '.apple | length' test.yaml)
   

2. env

   This is used to pass variables while using yq

   here are a few examples :

     capitalOfIndia=$(country="India" yq '.[env(country)].capital' test.yaml)
   

3. unique, sort

   Unique or/and Sort can be used with the help of pipe operator "|".

4. |, |=, +, +=

   • |

     Typically used to derive block of yaml

   • |=

     Used to update specific block of yaml

   • +=

     To Add a new entry and modify the parent yaml block as well

   • • To just add new entry but not update original

5. Test