I want to copy cp in terminal a symbolic relative link into another directory, and I would like the copy to keep relatively pointing to the original target ...
Use readlink /path/to/link to get the real file. cp `readlink /path/to/my/link` /foo/destination equals cp $(readlink /path/to/my/link) /foo/destination
What you need is N/a(=DIR/a), and N/b->../N/a; so just copy without dereferencing, using cp -P option. I believe this is also the default for cp ...
Use cp -P (capital P) to never traverse any symbolic link and copy the symbolic link instead. This can be combined with other options such as -R to copy a ...