Use environment variables for configuration

[DarkPark]

Would be nice to have it.

[jsumners]

Please provide details on what you are expecting. Is this request for the CLI tool?

[DarkPark]

@jsumners issue title is rather self-explanatory

instead of

myapp | pino-pretty --singleLine --colorize=1

would be nice to be able to use this

myapp | SINGLE_LINE=true COLORIZE=true pino-pretty

[jsumners]

issue title is rather self-explanatory

If that were the case I wouldn't have asked for more detail.

So, yes, you are looking for environment variable support in the CLI tool.

[DarkPark]

It also would be more natural to use boolean for COLORIZE instead of number.

[mahmoodhamdi]

I'd be happy to work on this! Based on the discussion, the feature would allow configuring pino-pretty via environment variables as an alternative to CLI flags.

A few thoughts on the implementation:

1. Naming convention: PINO_PRETTY_ prefix for all env vars (e.g. PINO_PRETTY_SINGLE_LINE=true, PINO_PRETTY_COLORIZE=true)
2. Priority: CLI flags > config file > env vars (lowest priority, as a fallback)
3. Boolean handling: Accept true/false/1/0 for boolean options like colorize and singleLine
4. Integration point: In bin.js where args are parsed, check for corresponding env vars before applying defaults

The mapping would be straightforward since CLI options can be converted to SCREAMING_SNAKE_CASE with the prefix (e.g. --singleLine → PINO_PRETTY_SINGLE_LINE, --colorize → PINO_PRETTY_COLORIZE).

Would this approach work? I can open a PR if there's agreement on the naming convention.