The man page for ln says that the `-f` switch can be used to, "remove existing destination files". So, if ./foo exists and is a directory, then `ln -sf ./bar ./foo` is the same as `rm ./foo; ln -s ./bar ./foo`.
But it doesn't work like that. Why is that?

It seems to work for me.. What exactly is not happening when you try to do this?

NOTE: in the context that you have written your example above, bar is the link being made, while foo is the folder you are linking to. So, by doing `ln -sf ./bar ./foo` it would delete ./bar if it exists (not foo) and recreate bar as the link.

I wasn't very clear at all in my examples so I'll try again.
I have a web application in php. In order to upgrade new versions, I create /MyApplication-V1/ , /MyApplication-V2/ and so forth. The actual application directory (/MyApplication) is a symbolic link pointing to one of those versions, making it easy to roll back code or upgrade as needed.
To start with, I create the folder pointing to version 1:
ln -s /MyApplication-V1/ /MyApplication
All is well. Now, when I'm ready to upgrade, I put new code in /MyApplication-V2 and change the symbolic link, thus:
ln -sf /MyApplication-V2 /MyApplication
This is where it fails for me. The link doesn't change and so I have to first remove the old link with `rm` then create a new link. if you'd like to try a test on your own, do this:
mkdir v1
mkdir v2
ln -s v1/ v
ln -sf v2/ v
after which v is still pointing to v1 even though you 'forced' it to point to v2.

OK, check out the first form of the use of ln.

try this:

ln -sf -T v1 v

then to redo it and point to v2:

ln -sf -T v2 v

you can also add the -v switch for a tiny bit of verbosity.

When we were doing it the other way, the symlink was appearing INSIDE the v2 or v2 folder () lol..
I just tried this new method (see the man page) and it DOES work for folders. I guess the behavior is slightly different for FILES vs FOLDERS.

sfjoe, it's not working because it is a link to a directory, you need to use the -n option to prevent it derefencing the link.

Thanks all. Like so many things, it's simple once you know how.