Description

Make the CLI fully composable with other *nix tools by adding plain output format, standardizing flags, implementing meaningful exit codes, and separating stdout/stderr.

Tasks

5.1 Add --output plain format

• Add plain format to view.Renderer
• Use tabs as delimiters for easy parsing with cut
• No headers in plain mode
• No color codes in plain mode
• Update all list commands to support plain output
• Examples that should work:
  • newrelic-cli apps list -o plain | cut -f1 (Just IDs)
  • newrelic-cli apps list -o plain | grep "production" (Filter)
  • newrelic-cli apps list -o json | jq -r '.[].id' (JSON processing)

5.2 Standardize flag behavior across all commands

• Global flags: --output/-o, --no-color, --verbose/-v
• Add --force/-f to destructive commands
• Add --limit/-l to all list commands

5.3 Implement meaningful exit codes

• Create internal/exitcode/exitcode.go:
  • Success = 0
  • GeneralError = 1
  • UsageError = 2
  • ConfigError = 3
  • AuthError = 4
  • APIError = 5
  • ServerError = 6
• Update root command error handling
• Document exit codes in README

5.4 Separate stdout and stderr

• Data output (tables, JSON, plain) → stdout only
• Status messages, progress, warnings → stderr only
• Update Renderer to accept separate writers

Integration Tests

Acceptance Criteria

• Plain output works with grep, cut, awk, xargs
• All flags documented in README
• Exit codes documented and consistent
• Piping works without status message pollution