---
title: "Using knitractive with Bash"
author: "Jeroen Janssens"
date: "`r Sys.Date()`"
output: github_document
---

*View the corresponding [bash.Rmd file](https://raw.githubusercontent.com/jeroenjanssens/knitractive/master/vignettes/examples/bash.Rmd) to learn more about how this page was generated.*

```{r setup, include = FALSE}
knitractive::start(name = "bash",
                   command = rexpect::cmd_docker(image = "ubuntu:20.04"),
                   prompt = rexpect::prompts$bash)
```

```{bash, include=FALSE}
PS1='$ '
apt-get update
apt-get install -y curl cowsay
alias cowsay='/usr/games/cowsay'
```

## Set a variable

```{bash set_name}
NAME=$(whoami)
```

## Spread a pipeline over multiple lines

```{bash multiple}
seq 100 |
grep 3 |
wc -l
```

## Retrieve a value

```{bash get_name}
cowsay "I am g${NAME}"
```

## Command substitution

```{bash cran}
echo "CRAN has $(
  curl -sL cran.r-project.org/web/packages/available_packages_by_date.html |
  grep "index.html" |
  wc -l
) packages"
```

## Take a screenshot of `top`

```{bash run_top}
top#! literal = FALSE
```

After two seconds we see the following screen:

```{bash start_top, highlight = FALSE, fullscreen = TRUE}
Enter#! literal = FALSE, hold = 3
```

Press **q** to exit `top`. 

```{bash exit_top, include = FALSE}
q#! enter = FALSE
```

## Send interrupt 

We can simulate pressing **CTRL-C** to quit long-running processes:

```{bash sleep, keep_last_prompt = TRUE}
sleep 1000 #! expect_prompt = FALSE
C-c #! wait = 1, literal = FALSE, expect_prompt = TRUE
```

*View the corresponding [bash.Rmd file](https://raw.githubusercontent.com/jeroenjanssens/knitractive/master/vignettes/examples/bash.Rmd) to learn more about how this page was generated.*