On 7/14/16, Jeff Law <l...@redhat.com> wrote: > On 07/14/2016 04:57 AM, Eric Gallager 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. > I don't have any BSD systems running. I can confirm that while "-f" > refers to files in the man page, it will happy delete the old symlink as > well. > > -bash-4.3$ ln -s /bin/ls jj > -bash-4.3$ ln -s -f /bin/bash jj > -bash-4.3$ ls -l jj > lrwxrwxrwx. 1 law law 9 Jul 14 13:22 jj -> /bin/bash > -bash-4.3$ which ln > /usr/bin/ln > -bash-4.3$ rpm -q --whatprovides /usr/bin/ln > coreutils-8.24-6.fc23.x86_64 > > Could you test this on your system? > > Jeff >
$ ln -s /bin/ls jj $ ln -s -f /bin/bash jj $ ls -l jj lrwxr-xr-x 1 root wheel 9 Jul 14 15:45 jj -> /bin/bash $ which ln /bin/ln $ rpm -q --whatprovides /bin/ln file /bin/ln is not owned by any package $ which rpm /sw/bin/rpm So apparently the "-f" flag properly overwrites symlinks that point to regular files, but I also did this in my gcc builddir: $ mkdir isl-0.1.2.3 $ ln -s isl-0.1.2.3 isl-s $ ln -sfv isl isl-s isl-s/isl -> isl $ ln -sfFv isl isl-s isl-s/isl -> isl $ ls -l isl-s lrwxr-xr-x 1 root wheel 11 Jul 14 07:03 isl-s -> isl-0.1.2.3 $ unlink isl-s $ ln -sfFv isl isl-s isl-s -> isl $ ls -l isl-s lrwxr-xr-x 1 root wheel 3 Jul 14 15:51 isl-s -> isl ...it just doesn't overwrite symlinks that point to a directory.
