Ubuntu – How Do I Link to /usr/lib or /opt From /usr/bin

This is Ubuntu 18.04 Desktop edition, running the default Gnome desktop.

I am trying to install FreeFileSync which is a downloadable .tar.gz file (from here: https://freefilesync.org/download.php). Once unpacked the tarball contains a directory, which in turn contains the binaries, sample .desktop files and another directory with resources like icons and sounds etc.

My initial approach was to copy the FreeFileSync directory to /usr/lib, and then link to it from /usr/bin:

sudo ln -s /usr/lib/FreeFileSync/FreeFileSync /usr/bin/freefilesync

… and then edit the .desktop file setting Exec=/usr/bin/freefilesync, and copy it to /usr/share/applications/FreeFileSync.desktop

The result is rather strange and I can't figure it out.

• If I run FreeFileSync from the applications menu it starts as expected
• If I open a terminal at /usr/bin and type "freefilesync" it starts as expected
• But if I run "freefilesync" in a terminal from anywhere other than /usr/bin I get this response: "Cannot determine real path for "freefilesync": No such file or directory [realpath]"

I have also tried putting the FreeFileSync directory in /opt but the same thing happens. I have other apps installed like Zoom and Citrix Receiver which both use symlinks to binary files from /usr/bin to /opt, which work perfectly, and the links look identical to the one I created above.

Any help with this is much appreciated as I'm scratching my head about what's going on here.