# R CLI App

Build command-line apps in R using the Rapp package.

- Repository: https://github.com/posit-dev/skills (551 stars)
- Category: Design
- License: MIT
- Last updated: 2026-10-28
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add posit-dev/skills --skill r-cli-app -g -a claude-code -y`
Codex: `npx skills add posit-dev/skills --skill r-cli-app -g -a codex -y`
Cursor: `npx skills add posit-dev/skills --skill r-cli-app -g -a cursor -y`
Gemini CLI: `npx skills add posit-dev/skills --skill r-cli-app -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add posit-dev/skills`

## Description

Build command-line apps in R using the Rapp package. Use when creating a CLI tool in R, adding argument parsing to an R script, turning an R script into a command-line app, shipping CLIs in an R package, or using Rapp (the alternative Rscript front-end). Also use for shebang scripts, exec/ directory in R packages, or subcommand-based R tools.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Building CLI Apps with Rapp

Rapp (v0.3.0) is an R package that provides a drop-in replacement for `Rscript`
that automatically parses command-line arguments into R values. It turns simple
R scripts into polished CLI apps with argument parsing, help text, and subcommand
support, with zero boilerplate.

**R ≥ 4.1.0** | **CRAN:** `install.packages("Rapp")` | **GitHub:** `r-lib/Rapp`

After installing, put the `Rapp` launcher on PATH:

```r
Rapp::install_pkg_cli_apps("Rapp")
```

This places the `Rapp` executable in `~/.local/bin` (macOS/Linux) or
`%LOCALAPPDATA%\Programs\R\Rapp\bin` (Windows).

---

## Core Concept: Scripts Are the Spec

Rapp scans **top-level expressions** of an R script and converts specific
patterns into CLI constructs. This means:

1. The same script works identically via `source()` and as a CLI tool.
2. You write normal R code, Rapp infers the CLI from what you write.
3. Default values in your R code become the CLI defaults.

Only top-level assignments are recognized. Assignments inside functions,
loops, or conditionals are not parsed as CLI arguments.

---

## Pattern Recognition: R → CLI Mapping

This table is the heart of Rapp, each R pattern automatically maps to a
CLI surface:

The rest: https://github.com/posit-dev/skills/blob/HEAD/r-lib/r-cli-app/SKILL.md