A symbolic link (or symlink) is actually a special entry that typically found on Unix systems, and can point to a file or directory in a transparent manner (see B on the diagram name below) .
Sometimes these links are in error following the renaming of a file or moving a directory. Here is a command to scan all the symbolic links of a system and to detect those errors.
Note the use of perl to test the proper functioning of the symbolic link:
find / -type l | perl -lne 'print if ! -e'
sudo find -L / -type l 2>/dev/null