file-truename

file-truename is a compiled Lisp function in `files.el'.

(file-truename FILENAME)

Return the truename of FILENAME.
If FILENAME is not absolute, first expands it against `default-directory'.
The truename of a file name is found by chasing symbolic links
both at the level of the file and at the level of the directories
containing it, until no links are left at any level.