On Thu, Jul 14, 2016 at 6:57 AM, Eric Gallager <eg...@gwmail.gwu.edu> wrote: > On 7/13/16, Jeff Law <l...@redhat.com> wrote: >> On 06/27/2016 08:10 PM, Eric Gallager wrote: >>> The last time I ran ./contrib/download_prerequisites, I already had >>> previous symlinks set up from a previous run of the script, so `ln` >>> followed the existing symlinks and created the new ones in the >>> directories to which the symlinks pointed. This patch should fix that >>> by removing the old symlinks before creating new ones. (For some >>> reason the `-f` flag to `ln` that was already there wasn't enough for >>> me.) Tested by running the script and ensuring that the new isl >>> symlink pointed to the correct directory, and that there were no bad >>> symlinks in the old isl directory. Could someone commit this trivial >>> patch for me, or something like it? I don't have write access. >> I'd really rather know why the "-f" flag didn't work for you. The whole >> point of -f is to remove the destination file first. >> >> Jeff >> > > Reading my ln manpage, it describes the "-f" flag like this: > > > -f If the target file already exists, then unlink it so that the > link may occur. (The -f option overrides any previous -i > options.) > > Okay, so that seems like it should do what you say, but the manpage > also describes a separate uppercase "-F" option: > > -F If the target file already exists and is a directory, then > remove it so that the link may occur. The -F option should be > used with either -f or -i options. If none is specified, -f is > implied. The -F option is a no-op unless -s option is speci- > fied. > > So it seems to imply that "-f" will only remove the destination file > if it's a regular file, while "-F" is needed if the destination file > is a directory. The page also has this to say about "-F" later: > > The -F option is FreeBSD extention and should not be used in portable > scripts. > > So this could be a BSD vs. GNU thing.
On GNU, -F means: -d, -F, --directory allow the superuser to attempt to hard link directories (note: will probably fail due to system restrictions, even for the superuser)