Why doesn't ln -s tell that it fails when creating a symlink to an existing symlinked directory?

Question

When running (on linux different ubuntu variations):

>ln -s dir_1 symlink_dir
>ln -s dir_2 symlink_dir

It fails without telling that it fails. But if you do the same thing on a file instead or, add v to the option it does tell you that it fails:

>ln -s file_1 symlinkg_file
>ln -s file_2 symlinkg_file

or

>ln -sv dir_1 symlink_dir
>ln -sv dir_2 symlink_dir

It fails with the error msg:

ln: failed to create symbolic link

For me this seems to be a very strange behaviour? Is there a reason for this?

Solution 1

Because in the second ln it doesn't fail it creates a

symlink_dir/dir_2 -> dir_2

symbolic link

Do a:

ls -l symlink_dir/dir_2

And you'll see a (probably broken) symlink there.

That's how ln is meant to work if the target is a directory (or a symlink to a directory).

A third ln could fail because there's already a dir_2 inside symlink_dir (aka dir_2).

Solution 2

As is desired, specifying -n will make ln fail in the second command:

$ ln -ns realdir symdir
$ ln -ns realdir symdir
ln: creating symbolic link `symdir' to `realdir': File exists

Note that -v is of course irrelevant to the outcome.

Comments

[user2139806]

I see. Then the second "ln -sv dir_2 symlink_dir" will then then print the error msg because it is a broken link or something.

[Kevin]

I would strongly recommend against putting a --force option in any alias, there's a reason they're not the default behavior.

[cjaphe]

Just -sn (or -ns) is sufficient to make ln fail as desired.