How to filter visual selection?

Question

Suppose we have some nice bunch of text:

Hello world

and we select the world in visual mode. Then we could filter the visual selection using a shiny command like this one:

:'<,'>!echo foobar

However, that would replace the entire line with foobar instead of just the world. Why is this, and how can we just replace the world?

Answer 1

The :! filter command always works on entire lines (this is as old as the original vi, embedding Ex commands that start with :), and the '<,'> range also only specifies lines.

You can use the venerable vis plugin to achieve your result; it offers a :B command that limits the following command to the visually selected text.

:'<,'>B !echo foobar

The plugin works for all kind of Ex commands; for :substitute within the selection you can also use the special \%V atom, though.