realpath package on Ubuntu.
Resolve all symbolic links and . and .. entries of a path recursively.
Prefer readlink which is more widespread by default in distros.
mkdir a
ln -s a b
cd a
touch a
ln -s a b
cd ..
realpath ./b/b
Output:
= "`pwd`/a/a"
readlink -f
Same as:
readlink ./b/b