sorting lines with vim

For e.g.

test.txt : 

z

y

x

w

v

u

If I say ->

:1,4 sort

test.txt will become

w

x

y

z

u

v

:.,+3 sort

will sort from current line to current line + 3.

:1,$ sort u

will sort and remove duplicates

To sort in reverse,
sort!

PS: This functionality doesn't work with IntelliJ Idea's vim plugin