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This page documents all command-line flags available in rbx-css. Flags are shared between compile and watch commands unless otherwise noted.

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Output flags

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-o, --output
string
Output file path for the compiled StyleSheet.Format inference:
  • .luau extension → Luau format
  • .rbxmx extension → RBXMX format
  • No extension → Luau format
Default: stdout (prints to console)Available in: compile, watch
rbx-css compile styles.css -o StyleSheet.luau
rbx-css compile styles.css -o StyleSheet.rbxmx
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--format
string
Explicitly set the output format, overriding automatic inference.Valid values:
  • luau - Generate Luau module (recommended)
  • rbxmx - Generate RBXMX model file (experimental)
Default: Inferred from --output file extensionAvailable in: compile, watch
rbx-css compile styles.css --format luau
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--name
string
default:"StyleSheet"
Name assigned to the root StyleSheet instance.Available in: compile, watch
rbx-css compile styles.css -o core.luau --name "CoreSheet"

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Warning flags

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--warn
string
default:"all"
Control the level of warnings emitted during compilation.Valid values:
  • all - Show all warnings (unsupported properties, selectors, units, etc.)
  • unsupported - Show only warnings about unsupported CSS features
  • none - Suppress all warnings
Available in: compile, watch
# Show all warnings
rbx-css compile styles.css --warn all

# Suppress warnings
rbx-css compile styles.css --warn none
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--strict
boolean
default:false
Treat warnings as errors. Compilation will fail (exit code 1) if any warnings are emitted.Useful for CI/CD pipelines where you want to enforce zero warnings.Available in: compile only
Not available in watch mode to avoid disrupting development workflow.
rbx-css compile styles.css -o out.luau --strict

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Output optimization

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--minify
boolean
default:false
Minify the generated Luau output by removing whitespace and comments.Only applies to: Luau format (has no effect on RBXMX output)Available in: compile only
rbx-css compile styles.css -o StyleSheet.luau --minify

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Token flags

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--tokens-sheet
boolean
default:false
Emit CSS custom properties (design tokens from :root) as a separate StyleSheet instance instead of embedding them in the main StyleSheet.Available in: compile only
rbx-css compile styles.css -o out.luau --tokens-sheet
This is useful when you want to share design tokens across multiple StyleSheets or manage them independently.

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Metadata flags

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--manifest
boolean
default:false
Generate a .manifest.json file alongside the output containing metadata about the compiled stylesheet.Manifest contents:
  • Classes that use overflow: scroll (helps tools like rbx-tsx upgrade Frame to ScrollingFrame)
  • Other compilation metadata
Requires: --output must be specified (doesn’t work with stdout)Available in: compile onlyExample:
rbx-css compile styles.css -o StyleSheet.luau --manifest
Produces:
  • StyleSheet.luau
  • StyleSheet.manifest.json

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Global flags

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--version
boolean
Display the rbx-css version number and exit.
rbx-css --version
# Output: 0.1.0
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--help
boolean
Display help information for a command.
rbx-css --help
rbx-css compile --help
rbx-css watch --help

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Flag compatibility matrix

Flagcompilewatch
-o, --output✓✓
--name✓✓
--format✓✓
--warn✓✓
--strict✓✗
--minify✓✗
--tokens-sheet✓✗
--manifest✓✗

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Examples

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Minimal compile

rbx-css compile styles.css

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Production build

rbx-css compile styles.css -o dist/StyleSheet.luau --strict --minify --manifest

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Development with watch

rbx-css watch src/styles -o StyleSheet.luau --warn none

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Multiple input files with custom name

rbx-css compile base.css theme.css components.css -o CoreSheet.luau --name "CoreSheet"

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