Using useradd with symbolic links in /etc/skel creates a
symbolic link in the user's home directory that points to a
file that is different than that in /etc/skel.

For example, with "core -> /dev/null" in /etc/skel, the file
that is created in the home directory is
"core -> /dev/null???`???????_???"

This outcome is the same for any symbolic link to any file;
however, the filename that the link points to in the home
directory is different for each.