Why create a link like this: ln -nsf?
From the BSD man page:
-f If the target file already exists, then unlink it so that the link
may occur. (The -f option overrides any previous -i options.)
-n 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.
the -n
option (together with -f
) forces ln
to update a symbolic link to a directory. what does that mean?
suppose you have 2 directories
- foo
- bar
and an existing symbolic link
- baz -> bar
now you want to update baz to point to foo instead. if you just do
ln -sf foo baz
you would get
- baz/foo -> foo
- baz -> bar (unchanged), and thus
- bar/foo -> foo
if you add -n
ln -sfn foo baz
you get what you want.
- baz -> foo
that is what 'no-dereference' means: do not resolve an existing link and place the new link inside that directory, but rather just update it.
Here are all the options to ln. You'll find -n and -f in here.
-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. Otherwise, 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.