In r-lib/asciicast: Create 'Ascii' Screen Casts from R Scripts

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  fig.path = "man/figures/README-",
  out.width = "100%",
  asciicast_at = "all",
  asciicast_theme = if (Sys.getenv("IN_PKGDOWN") == "true") "pkgdown" else "readme"
)
asciicast::init_knitr_engine()

asciicast

Turn R scripts into terminal screencasts

asciicast takes an R script and turns it into an asciinema cast. It can simulate typing, and records all terminal output in real time as it happens.

Features

Input is an R script, output is a v2 asciicast recording.
Record all terminal output in real time, as it happens.
Simulate typing in the commands, with a configurable, randomized speed.
Alternatively, whole comment blocks or expressions can just appear on the screen.
Convert casts to SVG images using svg-term. The package comes with its own svg-term bundle, no external dependencies are needed.
Render a single frame of a cast as an SVG image.
Configurable delay at the beginning, at the end and between paragraphs.
HTML widget, to be used in Rmarkdown documents, e.g. in vignettes.
Read casts from asciinema JSON files (version 2), or from https://asciinema.org directly.
Special knitr engine to create R markdown files with ascii casts. See the asciicast-demo vignette.
Create ascii casts in GitHub READMEs via animated SVG files. See an example in inst/examples or the README.Rmd source of the README file you are reading.

Limitations

asciicast works best in an UTF-8 locale. It also works well if all output is ASCII, but non-ASCII output might cause problems (https://github.com/r-lib/asciicast/issues/36).

Installation

You can install the released version of asciicast from CRAN:

install.packages("asciicast")

Examples

See the inst/examples directory for these examples.

Hello world

The input script:

The result:

```{asciicast, code = readLines("inst/examples/hello.R"), cache = TRUE}

### Asciicast demo in asciicast

Input script that uses asciicast itself:

```r

```{asciicast, code = readLines("inst/examples/asciicast.R"), cache = TRUE}

### Errors are recorded

Input script with errors:

```r

{asciicast, code = readLines("inst/examples/errors.R"), cache = TRUE}

Related tools

asciinema: https://asciinema.org/
The original terminal session recorder: https://github.com/asciinema/asciinema
svg-term: https://github.com/marionebl/svg-term, https://github.com/marionebl/svg-term-cli