[SOLVED] how to use tr or sed to replace line breaks in a YAML file to single line string with '\n'

Issue

I am using a bash shell and trying to process text file to replace line breaks with a single line string with "\n"s. Example:

Source file:

apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: LOOOONG-STRING
    server: https://1.2.3.4:8443
  name: cluster-name
contexts:
- context:
    cluster: cluster-name
    user: cluster-admin
  name: cluster-admin@cluster-name
current-context: cluster-admin@cluster-name
kind: Config
preferences: {}
users:
- name: cluster-admin
  user:
    client-certificate-data: LOOOONG-STRING
    client-key-data: LOOOONG-STRING

Desired Output

apiVersion: v1\nclusters:\n- cluster:\n    certificate-authority-data: LOOOONG-STRING\n    server: https://1.2.3.4:8443\n  name: cluster-name\ncontexts:\n- context:\n    cluster: cluster-name\n    user: cluster-admin\n  name: cluster-admin@cluster-name\ncurrent-context: cluster-admin@cluster-name\nkind: Config\npreferences: {}\nusers:\n- name: cluster-admin\n  user:\n    client-certificate-data: LOOOONG-STRING\n    client-key-data: LOOOONG-STRING

I tried many tr and sed examples here and cannot get it done. thanks.

Solution

Try this:

sed -e :a -e '$!N;s/\n/\\\n/;ta' file

With Gnu sed, you may need to escape new line only once:

sed -e :a -e '$!N;s/\n/\\n/;ta' file

All lines are joined and new line characters replaced with \\\n.

You can add the -i flag to edit the file in place or redirect output to a new file:

sed -e :a -e '$!N;s/\n/\\\n/;ta' file > newfile

Answered By - SLePort