How get full path to target of link

If I have a symbolic link /var/opt/foo created with ln -fs /path/to/target/dir foo. How can I in a script that sees only the link get /path/to/target/dir?

What I want to achieve in the script is rm -rf /path/to/target/dir before I do ln -fs /path/to/another/dir foo.

Solution 1:

link=/var/opt/foo

target=$(readlink "$link")

$target is now the target of the link, exactly as it was stored in the filesystem.

Symlinks can be relative, though, so this would be better for normal usage:

target=$(readlink -f "$link")

Note that this uses readlink from GNU Coreutils, which may not exist in BSD and other systems.

Edit: readlink -f works on BSDs, as long as the link target exists. realpath is another, BSD-only, tool that works in a similar way.