Question 1

How do I pretty print JSON with underscore-cli?

Accepted Answer

Use the 'print' or 'pretty' command, e.g., 'cat data.json | underscore print --color'. This outputs formatted JSON with smart whitespace and optional colorization, making it highly readable for debugging or inspection.

Question 2

Can underscore-cli convert JSON to CSV?

Accepted Answer

Not directly; it focuses on JSON and text formats. For CSV conversion, you might need to combine it with other tools, as underscore-cli can output data in 'text' format for further processing with commands like awk or sed.

Question 3

How to extract all titles from a nested JSON array?

Accepted Answer

Use the 'select' command with a JSONSelect query, e.g., 'cat data.json | underscore select .title', or chain commands like 'extract' and 'pluck' for specific fields, as demonstrated in the Reddit API example.

Question 4

Underscore-cli vs jq: which should I use?

Accepted Answer

Underscore-cli is better if you're comfortable with JavaScript and need complex transformations using libraries like underscore. Jq is a standalone binary with a domain-specific language, often faster and lighter for simple queries or in environments without Node.js.

Question 5

How to install underscore-cli on Ubuntu?

Accepted Answer

First install Node.js via apt or nvm, then run 'npm install -g underscore-cli'. Ensure you have npm installed globally, and check for optional dependencies like CoffeeScript if needed for specific features.

Question 6

Does underscore-cli support streaming for large files?

Accepted Answer

No, it currently reads all input into memory. The README notes that stream processing is a planned feature but not yet implemented, so it's not suitable for very large files where memory efficiency is critical.

Question 7

How to use CoffeeScript expressions with underscore-cli?

Accepted Answer

Use the '--coffee' flag or rely on auto-detection; for example, 'underscore map --coffee "value?.property"' to handle optional chaining. Auto-detection warns if ambiguous expressions are used, so specifying the flag is recommended for clarity.

underscore-cli

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