如何使用 bash 脚本在文件中的特定单词或行后添加一行？

Question

This is file content

  name: kubernetes
contexts:
- context:
    cluster: kubernetes
    user: kubernetes-admin
  name: kubernetes-admin@kubernetes
current-context: kubernetes-admin@kubernetes
kind: Config
preferences: {}
users:
- name: kubernetes-admin
  user:

i need to add the following block of code after the word contexts which is second line in above file content

- context:
       cluster: kubernetes
       namespace: myco-dev
       user: kubernetes-admin
     name: myco/DEV
   - context:
       cluster: kubernetes
        namespace: myco-ua
        user: kubernetes-admin
     name: myco/UA

so the final output should look like

contexts:
- context:
    cluster: kubernetes
    user: kubernetes-admin
  name: kubernetes-admin@kubernetes
- context:
    cluster: kubernetes
    user: kubernetes-admin
    namespace: myco-dev
  name: myco/DEV
- context:
    cluster: kubernetes
    user: kubernetes-admin
    namespace: myco-ua
  name: myco/UA
current-context: kubernetes-admin@kubernetes
kind: Config
preferences: {}

Answer 1

I don't know YAML which is according to some comments that the data is from that type. In the assumption of the data will come from files, let say file1 and file2. We can use ed. (again I don't know YAML or where the data is coming from)

Content of file1 is

  name: kubernetes
contexts:
- context:
    cluster: kubernetes
    user: kubernetes-admin
  name: kubernetes-admin@kubernetes
current-context: kubernetes-admin@kubernetes
kind: Config
preferences: {}
users:
- name: kubernetes-admin
  user:

Content of file2 is

- context:
       cluster: kubernetes
       namespace: myco-dev
       user: kubernetes-admin
     name: myco/DEV
   - context:
       cluster: kubernetes
        namespace: myco-ua
        user: kubernetes-admin
     name: myco/UA

To insert the content of file2 to file1 we do.

 printf '%s\n' '2 r file2' w | ed -s file1

Checkout the content of file1

cat file1

  name: kubernetes
contexts:
- context:
       cluster: kubernetes
       namespace: myco-dev
       user: kubernetes-admin
     name: myco/DEV
   - context:
       cluster: kubernetes
        namespace: myco-ua
        user: kubernetes-admin
     name: myco/UA
- context:
    cluster: kubernetes
    user: kubernetes-admin
  name: kubernetes-admin@kubernetes
current-context: kubernetes-admin@kubernetes
kind: Config
preferences: {}
users:
- name: kubernetes-admin
  user:

The number 2 is the address aka line number

The r afaik is read which means read file2

The w means write.

see

 man(1p) ed