yvar - replace placeholders in files

yvar is a tiny command-line tool that replaces placeholders, that look like $_{ FOO }, with some other value. For example, look at this example.yml file:

example:
  answer: $_{ ANSWER }

Now run yvar:

yvar example.yml example.out.yml --ANSWER 42

The result will be the following file named example.out.yml:

example:
  answer: 42

yvar should work with all kinds of text files, e.g. json.

I'm not to sure if this tool has any real-world use cases, but I personally use it in my continuous deployment setup to create environment specific docker-compose.override.yml files during builds.

Also if you have bugs or improvements, feel free to open an issue on GitHub.

Install

npm install yvar

or if you want to use it globally with the yvar command

npm install -g yvar

Use

Any yvar command has to following structure:

yvar INPUT_FILE OUTPUT_FILE [VARS]

• INPUT_FILE: path to file that contains placeholders
• OUTPUT_FILE: path of file that holds result
• [VARS]: List all placeholders with their replacement using --. I.e. if you want to replace $_{ FOO } with "bar", append --FOO bar to the command

License

MIT