How to find out the dependencies of an already installed (portable) application in Linux?

Question

linux

How to find out the list of all necessary packages / libraries for a particular portable application to work on Linux, if this application has neither a repository nor a deb package?
Specifically, the task is related to FreeFileSync which does not want to launch a folder selection dialog in KDE Plasma on Kubuntu 14.04.05. If you install the whole xubuntu-desktop it starts working, unless xfce4 doesn't. I don't want to install the whole Xubuntu-desktop, it causes problems in KDE (a number of environment settings are reset, the visible plasma-desktop window hangs in the upper left corner and the corresponding item in the taskbar). In general, you need to somehow find out what exactly FreeFileSync lacks. How can this be done? Or just tell him what he needs. I looked in the Docks - I did not find it.

Answer 1

ldd exec_name
And see what libraries he needs.
Option number 2 - run in the console and look at what "swears".

Answer 2

try:
Replace package_name with the name of your package.

Answer 3

In case someone is interested in more options, here they gave me another one and helped to narrow down the circle of necessary libs, although a reliable and universal way to find out dependencies was never really found. This one is especially interesting , though I still haven’t figured out whether he gave me what I need.