sort number and size

[Imen Turki]

the current solution does not sort file size correctly.

Exemple :
a-100 MB
b- 2 kB
c- 50MB
d- 1 G
e- 190 KB

using sort:

d - 1G
a- 100 MB
e- 190 KB
b- 2 KB
c- 50 MB

Any one resolve this issue.