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Stdout mode (default)

Without -i, nesdit reads the input file, applies the query, and writes the result to stdout. The file on disk is never touched.

Basic usage

nesdit config.json --query '.env = "production"'

Input (config.json):

{"env":"staging","replicas":1}

Stdout:

{"env":"production","replicas":1}

config.json on disk: unchanged.

Piping to another command

Because the result goes to stdout, you can pipe it anywhere:

nesdit values.yaml --query '.image.tag = "v2.0"' | kubectl apply -f -

Or redirect to a new file:

nesdit staging.json --query '.env = "production"' > production.json

Cross-format transcoding

Use --output-format to produce a different format than the input:

nesdit input.json --output-format yaml

Input (input.json):

{"name":"alice","version":1}

Stdout:

name: alice
version: 1

See examples/formats for all six format combinations.

Identity query

The default query is . (identity). If you omit --query, nesdit normalises and round-trips the file through its decoder and encoder:

nesdit config.json

This is useful for normalising a file to nesdit's canonical encoding. The output is always idempotent: running it a second time produces byte-identical output.

Multiple files to stdout

When multiple files are passed (all the same format), outputs are concatenated with the appropriate framing:

  • YAML files: --- separators between documents.
  • JSON files: one JSON object per line (JSONL).
nesdit a.yaml b.yaml --query '.version = 2'

Output:

---
name: alpha
version: 2
---
name: beta
version: 2

Warning

Mixing formats in one invocation is an error: 

nesdit a.json b.yaml --query '.'

nesdit: error: format.mixed: yaml (b.yaml), json (a.json): single invocation spans multiple formats