Ubuntu – Impossible to launch graphic executables in nautilus

Just create a folder ~/bin. Add the following line in your ~/.bashrc,

export PATH=/home/$USER/bin:$PATH

Source ~/.bashrc from terminal as,

. ~/.bashrc

Put files with execution permission inside ~/bin.

Tl;dr

There's no difference, aside from the fact that a compiled executable might be linked against a shared object but not against an executable.

In general, there are two ways to compile¹ an executable:

• Using static linking: external libraries included in the source code are compiled and the compiled library (or object in the linker's perspective) is added to the executable itself;
• Using dynamic linking: external libraries included in the source code are compiled but a link to the compiled library (or object in the linker's perspective) is added to the executable (and the compiled libraries / objects are loaded by the linker at run-time if needed);

There are advantages / disadvantages in using each of these methods, but that's not the point of the question;

• /bin/ntfsck and /usr/bin/gawk are shared objects: this means that an executable might be compiled and then linked against them to use their functionalities;
• /bin/echo is an executable: this means that an executable might not be compiled and then linked against it to use its functionalities;

So /bin/ntfsck and /usr/bin/gawk are technically compiled libraries (or objects in the linker's perspective), but, as one may have forsaw, nothing prevents a shared object from being run as an executable.

On a side note, notice also that file reports (for each of them):

dynamically linked (uses shared libs)

This means that each of them is dynamically linked to (and likely uses) other shared objects as well.

_{1. "Compile" intended in its broader acceptation, which includes preprocessing, compilation and linking.}