brew/Library/Homebrew/cmd/cleanup.rb

#:  * `cleanup` [`--prune=`<days>] [`--dry-run`] [`-s`] [<formula/cask> ...]:
#:    Remove stale lock files and outdated downloads for formulae and casks,
#:    and remove old versions of installed formulae. If arguments are specified,
#:    only do this for the specified formulae and casks.
#:
#:    If `--prune=`<days> is specified, remove all cache files older than <days>.
#:
#:    If `--dry-run` or `-n` is passed, show what would be removed, but do not
#:    actually remove anything.
#:
#:    If `-s` is passed, scrub the cache, including downloads for even the latest
#:    versions. Note downloads for any installed formula or cask will still not
#:    be deleted. If you want to delete those too: `rm -rf $(brew --cache)`

require "cleanup"
require "cli_parser"

module Homebrew
  module_function

  def cleanup
    CLI::Parser.parse do
      switch "-n", "--dry-run"
      switch "-s"
      flag   "--prune="
    end

    cleanup = Cleanup.new(*args.remaining, dry_run: args.dry_run?, scrub: args.s?, days: args.prune&.to_i)

    cleanup.clean!

    unless cleanup.disk_cleanup_size.zero?
      disk_space = disk_usage_readable(cleanup.disk_cleanup_size)
      if args.dry_run?
        ohai "This operation would free approximately #{disk_space} of disk space."
      else
        ohai "This operation has freed approximately #{disk_space} of disk space."
      end
    end

    return if cleanup.unremovable_kegs.empty?

    ofail <<~EOS
      Could not cleanup old kegs! Fix your permissions on:
        #{cleanup.unremovable_kegs.join "\n  "}
    EOS
  end
end