Applications of on.exit()

• Set an R option
• Set an environment variable
• Change working directory
• Create a file or directory
• Create a resource on an external system

neat <- function(x, sig_digits) {
  op <- options(digits = sig_digits)
  on.exit(options(op), add = TRUE)
  print(x)
}

neat(pi, 2)

## [1] 3.1

pi

## [1] 3.141593