I know that there is a command that lists me the libs and respective versions a software was linked against.
Something with ld or libtool?
But I just cannot remember. Spent some time on google but didn't come up with anything useful.
Try ldd binary-exec
To find what it directly needs:
ld and libtool are used at compile/link time. They aren't useful once you have an app.
EDIT I can see by later answers you were asking about OSX, but I want to add to my answer on Linux tools:
One thing I forgot to mention, quite a while ago; you asked about versions. Neither
Another way would be to use objdump.
This shows all needed dependencies only for this binary. Very useful.