Creating a soft symbolic link from R on Windows

Question

I'd like to create a soft symbolic link to a file from within R on Windows (with Mklink). It fails because I cannot tell R to "run it as administrator". Is there any way I can do this?

I did manage to create hard symbolic file links, however:

path_src <- file.path(tempdir(), "test.txt")
write("Hello World!", file = path_src)
path_tgt <- file.path(tempdir(), "test_symlink.txt")
shell(sprintf("mklink /H %s %s", 
  normalizePath(path_tgt, mustWork = FALSE),
  normalizePath(path_src)
))

Note how the file at path_tgt reflects the changes made to path_src:

write("HELLO WORLD!", file = path_src, append = TRUE)

Yet, this fails:

path_tgt_2 <- file.path(tempdir(), "test_symlink_2.txt")
> shell(sprintf("mklink /D %s %s", 
  normalizePath(path_tgt_2, mustWork = FALSE),
  normalizePath(path_src)
))
Ihre Berechtigungen reichen nicht aus, um diesen Vorgang auszufhren.
Warning messages:
1: running command 'C:\Windows\system32\cmd.exe /c mklink /D C:\Users\Thyson\AppData\Local\Temp\Rtmpum73ZU\test_symlink_2.txt C:\Users\Thyson\AppData\Local\Temp\Rtmpum73ZU\test.txt' had status 1 
2: In shell(sprintf("mklink /D %s %s", normalizePath(path_tgt_2, mustWork = FALSE),  :
  'mklink /D C:\Users\Thyson\AppData\Local\Temp\Rtmpum73ZU\test_symlink_2.txt C:\Users\Thyson\AppData\Local\Temp\Rtmpum73ZU\test.txt' Ausführung mit Fehlerkode 1 fehlgeschlagen

Note

Due to a German version of Windows I can't seem to get the errors in English. The first line translates to somewhat along the lines of "You don't have enough authorization in order to carry out this process"

Answer 1

Run R as administrator. Then when you run "Mklink" from within R, you are the administrator.

Actually, you can also use the R function file.symlink to create symbolic links.

Answer 2

Since 2016 (Windows 10 Insiders build 14972), you can also make symbolic links without administrator rights if you enable the developer mode (in Settings>Update and Security>For developers).

This works in the Windows console with mklink, but it doesn't seem that R's file.symlink() works (as of R 4.0.3), possibly because of the dwFlags that needs to be set.

For calling it from R, I needed to add " when the path contains spaces:

shell(sprintf('mklink "%s" "%s"', 
              normalizePath(link, mustWork = FALSE),
              normalizePath(original)
))

For directories, you can also consider the use of Sys.junction() which is somewhat equivalent to symlinks.