# headson
Budget‑constrained JSON preview for the terminal.
## Install
Using Cargo:
cargo install headson
From source:
cargo build --release
target/release/headson --help
## Usage
headson [FLAGS] [INPUT...]
- INPUT (optional, repeatable): file path(s). If omitted, reads JSON from stdin. Multiple input files are supported.
- Prints the preview to stdout. On parse errors, exits non‑zero and prints an error to stderr.
Common flags:
- `-n, --budget <BYTES>`: per‑file output budget. When multiple input files are provided, the total budget equals `<BYTES> * number_of_inputs`.
- `-N, --global-budget <BYTES>`: total output budget across all inputs. Useful when you want a fixed-size preview across many files (may omit entire files). Mutually exclusive with `--budget`.
- `-f, --template <json|pseudo|js>`: output style (default: `pseudo`)
- `-m, --compact`: no indentation, no spaces, no newlines
- `--no-newline`: single line output
- `--no-space`: no space after `:` in objects
- `--indent <STR>`: indentation unit (default: two spaces)
- `--string-cap <N>`: max graphemes to consider per string (default: 500)
Notes:
- With multiple input files:
- JSON template outputs a single JSON object keyed by the input file paths.
- Pseudo and JS templates render file sections with human-readable headers.
- Using `--global-budget` may truncate or omit entire files to respect the total budget.
Examples:
- Read from stdin with defaults:
cat data.json | headson
- Read from file, JS style, 200‑byte budget:
headson -n 200 -f js data.json
- JSON style, compact:
headson -f json -m data.json
- Multiple files (JSON template produces an object keyed by paths):
headson -f json a.json b.json
- Global limit across files (fixed total size across all files):
headson -N 400 -f json a.json b.json
Show help:
headson --help