From commandline:

ln -s /lib/libssl.so.0.9.7a /lib/libssl.so.0.9.7


I know how to make a symlink between a file in one directory to another directory
that is essentially just the same what I did above, there is no difference whether the destination is in the same directory. About the existence of the target: if it does not exist, it will be created, if it exists, ln will fail and report that the file already exists.

If you want to override the possibly existing file, the syntax is:

ln -sf <source> <target>

which forces (-f) the symlink to be created even if the target file exists. This is dangerous since you might override some important files if you are not really sure what you are doing. So I suggest you don't use -f.

Symlinks are deleted like normal files, with rm. To see what files are symlinks:

ls -la

should show the symlinks like libssl.so.0.9.7 -> libssl.so.0.9.7a