You are mixing up separate, rather independent aspects:
1. Symbolic links
Symbolic links (symlinks) in Linux allow to create access to a certain folder from within another folder. For example:
sudo ln -s /media/phil/4A05-B4F6 /olddisc
will make sure the contents of /media/phil/4A05-B4F6 can also be seen in /olddisc.
For practical purposes, a symbolic link feels and behaves just like a real directory. You can thus copy contents to and from it.
2. Copying an entire directory tree
There are a number of ways to do that. The standard cp (copy) command can do that when executed with the appropriate option, -R. rsync is a more specialized tool for that job, and has the powerfull feature where it can only copy new or updated files from a source directory to a target directory, making it rather perfect for synchronizing two directories or maintaining backups.
Thus, you could copy an entire directory tree with the command:
cp -R /media/phil/4A05-B4F6/* /media/phil/3117e488-bf89-426e-a606-55e8397cf1ee
Because you created symbolic links, the same effect can be achieved with
cp -R /olddisc /pcdisc
rsync can be used with the -a (archive) flag to "mirror" directories:
rsync -av /olddisc/ /pcdisc/
(pcdisk should already exist, and the trailing / are important: keeping them in or leaving them out has a different meaning and can have a different outcome depending on whether the target does exist or not).
Remark on using sudo
*Avoid the use of sudo as much as possible. Only use it for system tasks, and when you know what you are doing. *For copying user data, you should not have to use sudo.
On Linux, a user can copy/move/delete in directories where permission has been granted. You automatically have permissions for files in your home directory, and for files in removable hard drives that you connect while you are logged in.
In any other case, for example an internal partition, use sudo to grant yourself permissions. Then proceed manipulating your user data as a user. Only use sudo to copy, move or delete system files.
