We made a CLI for using Costflow Syntax in your terminal. With Costflow CLI, you can create postings easily, and the output will be saved to your ledger file directly (only Beancount format is supported at the moment). Costflow CLI is completely running offline (except for $ and price command).
npm install -g costflow-cli
Check the docs: https://docs.costflow.io/cli/
Costflow CLI is also open source on Github: https://github.com/costflow/cli.