问题
So I created a symlink:
ln -s /location/to/link linkname
Now I want to change the location that the symlink links to. How do I do that? is there a way to do it without deleting it first?
回答1:
You could create the new link with a different name, then move it to replace the old link.
ln -s /location/to/link linkname
Later
ln -s /location/to/link2 newlink
mv newlink linkname
If newlink and linkname are on the same physical device the mv should be atomic.
回答2:
Try ln -sf new_destination linkname.
回答3:
If the symlink targets are directories, you need to add the -T flag to the mv command, otherwise it moves the new symlink in to the target directory of the old symlink.
Example of atomically switching a website to a new version:
Original setup - website is stored in www1 directory, vhost pointing at www symlink:
ln -s www1 www
Browse to website, see old version.
Put new website files in new www2 directory.
Set up new symlink to new website:
ln -s www_new www2
Move www symlink to directory of new website:
mv -T www_new www
Browse to website, see new version immediately.
回答4:
Just change the symlink target:
# ln -sfT /path/to/new/target linkname
This is an instant, atomic change.
回答5:
For directories, you want to do: ln -sfT /location/to/new/target old_linkname
回答6:
On OSX, the man page for ln says you can do it like this
ln -shf /location/to/link link name
From the man page:
The options are as follows:
-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 specified.
-h If the target_file or target_dir is a symbolic link, do not follow it. This is most useful with the -f
option, to replace a symlink which may point to a directory.
-f If the target file already exists, then unlink it so that the link may occur. (The -f option overrides any
previous -i options.)
-i Cause ln to write a prompt to standard error if the target file exists. If the response from the standard
input begins with the character `y' or `Y', then unlink the target file so that the link may occur. Other-
wise, do not attempt the link. (The -i option overrides any previous -f options.)
-n Same as -h, for compatibility with other ln implementations.
-s Create a symbolic link.
-v Cause ln to be verbose, showing files as they are processed.
回答7:
No. The symlink system call will return EEXIST if newpath already exists. You can only link from a new node in the filesystem. What's the requirement here? If you're worried about a race due to the non-atomicity of the unlink/symlink calls, then you might want to rethink the architecture a little to provide synchronization elsewhere. There have been some scary security bugs introduced by this kind of thing.
回答8:
Chain the commands like this:
rm currentlink && ln -s /path/to/link currentlink
The first command removes the existing one and the 2nd immediately creates it again.
回答9:
As others have mentioned, you basically have to delete the symlink first, either manually or by passing the -f flag to the ln utility.
Years ago, I had to make small edits to symlinks pretty frequently, so I wrote a simple readline-based utility (edln) to make this less annoying. In case anyone else finds it useful, I've put it online at https://github.com/jjlin/edln/.
edln will display the original symlink target; you can then use the arrow keys, or standard readline keystrokes (M-b, M-f, C-d, etc.) to move around and edit the target.
回答10:
Just googled, found no good answer and had to solve myself:
ln -f -s -T `readlink SomeLibrary | sed 's/version.old/version.new/'` SomeLibrary
Editing by definition means not recreating from scratch but changing partly. Any answer requiring to memorize a path, maybe long or with weird symbols, is definitely bad.
来源：https://stackoverflow.com/questions/1727280/is-there-a-way-to-edit-a-symlink-without-deleting-it-first