curlThe function upload_ftp() runs the command curl -T file
server to upload a file to an FTP server if the system command
curl is available, otherwise it uses the R package curl. The
function upload_win_builder() uses upload_ftp() to upload
packages to the win-builder server.
upload_ftp(file, server, dir = "")upload_win_builder(
  file = pkg_build(),
  version = c("R-devel", "R-release", "R-oldrelease"),
  server = c("ftp", "https")
)
Status code returned from system2() or
curl::curl_fetch_memory().
Path to a local file.
The address of the FTP server. For upload_win_builder(),
server = 'https' means uploading to
'https://win-builder.r-project.org/upload.aspx'.
The remote directory to which the file should be uploaded.
The R version(s) on win-builder.
These functions were written mainly to save package developers the trouble of going to the win-builder web page and uploading packages there manually.