how to update a symbolic link target (ln -f -s not working)

Question

I'm using

ln -f -s /var/www/html/releases/build1390 app-current

to update symbolic link "app-current" with a new destination. However, this doesn't work, the link "app-current" keeps it original destination, however, I don't get any errors...

I'd rather not remove the link and recreate it, just update the target of an existing link. Is that possible?

Answer 1

That works for me, what is the output of strace ln -f -s /var/www/html/releases/build1390 app-current ?

Oh, since it is a directory you need to add -n for no dereference and this should solve the issue. -f is really more of a convenience since adding the -f just causes it to unlink anyways. Although I guess it would probably happen a few hundred ms faster on a normally loaded system.

For example, if arf already points to /home:

strace With -n:

strace ln -n -f -s / arf
...
symlink("/", "arf")           = -1 EEXIST (File exists)
unlink("arf")                           = 0
symlink("/", "arf")           = 0

strace Without -n:

strace ln -f -s / arf
...
write(2, "ln: "..., 4ln: )                  = 4
write(2, "`arf/': cannot overwrite director"..., 34`arf/': cannot overwrite directory) = 34
write(2, "\n"..., 1)                    = 1

So without the -n arf gets dereferenced so ln treats it as arf as if it were actually /. In your particular example, if there is no error, I think you have probably created a new symbolic link inside of /var/www/html/releases/build1390 app-current and will want to clean that up.