It’s quite simple: You create a symbolic link in ~
that points to ./abc
in that directory. The pathname of a symbolic link must be valid in the context of the directory it is in¹. If you indeed want to point to the file that is in your now current directory, you must use the full path.
- The link must be valid if you want to use it. It can point into nothingness or to a file that does not exist. That can be a good thing, as the file might have been there before and can reappear any time, and the symbolic link will then point to it again.