cli

Helpers for Developing Command Line Interfaces

A suite of tools to build attractive command line interfaces (CLIs), from semantic elements: headers, lists, alerts, paragraphs, etc. Supports theming via a CSS-like language. It also contains a number of lower level CLI elements: rules, boxes, trees, and Unicode symbols with ASCII alternatives. It integrates with the crayon package to support ANSI terminal colors.

Features

Build a CLI using semantic elements: headings, lists, alerts, paragraphs.
Theming via a CSS-like language.
Terminal colors via the crayon package.
Create cli elements in subprocesses, using the callr package.
All cli text can contain interpreted string literals, via the glue package.
Support for pluralized messages.

Installation

Install the stable version from CRAN:

install.packages("cli")

Short tour

Some of the more commonly used cli elements, and features.

Short alert messages

One liner messages to inform or warn.

pkgs <- c("foo", "bar", "foobar")
cli_alert_success("Downloaded {length(pkgs)} packages.")

db_url <- "example.com:port"
cli_alert_info("Reopened database {.url {db_url}}.")

cli_alert_warning("Cannot reach GitHub, using local database cache.")

cli_alert_danger("Failed to connect to database.")

cli_alert("A generic alert")

Headings

Three levels of headings.

cli_h1("Heading 1")

cli_h2("Heading 2")

cli_h3("Heading 3")

Lists

Ordered, unordered and description lists, that can be nested.

fun <- function() {
  cli_ol()
  cli_li("Item 1")
  ulid <- cli_ul()
  cli_li("Subitem 1")
  cli_li("Subitem 2")
  cli_end(ulid)
  cli_li("Item 2")
  cli_end()
}
fun()

Themes

Theming via a CSS-like language.

fun <- function() {
  cli_div(theme = list(span.emph = list(color = "orange")))
  cli_text("This is very {.emph important}")
  cli_end()
  cli_text("Back to the {.emph previous theme}")
}
fun()

Command substitution

Automatic command substitution via the glue package.

size <- 123143123
dt <- 1.3454
cli_alert_info(c(
  "Downloaded {prettyunits::pretty_bytes(size)} in ",
  "{prettyunits::pretty_sec(dt)}"))

Pluralization

Pluralization support.

nfiles <- 3
ndirs <- 1
cli_alert_info("Found {nfiles} file{?s} and {ndirs} director{?y/ies}.")

Documentation

See at https://cli.r-lib.org/ and also in the installed package: ?"inline-markup", ?containers, ?themes, ?pluralization.

cli