Groundhog in a nutshell.

Make your R scripts reproducible by replacing library(pkg) with groundhog.library(pkg,date)

  • groundhog.library() loads packages & their dependencies as available on chosen date on CRAN.
  • Packages get automatically installed if needed.
  • Installation keeps, rather than replaces, existing other versions of that package.
  • All operating systems and R versions install/load the same package version
  • If you want to discontinue using groundhog, simply:¬† groundhog.library(pkg,date).


pkgs <- c("rio","metafor")

groundhog.library(pkgs, "2023-09-01")