How can I wrap text to some length in Vim?

Question

Let's speak of relative measures. My Vim looks like:

aaaaaaaaaaaaa 
bbbbbbbbbbbbb 
ccccccccccccc 
etc

I would like it to be smaller:

aaaaa
aaaaa
bbbbb
bbbbb
ccccc
ccccc
etc

How can I get it? And how can I manage setting the length of such a block?

Answer 1

Using fold(1) is one possibility:

:%!fold -w5

Result:

aaaaa
aaaaa
aaa 
bbbbb
bbbbb
bbb 
ccccc
ccccc
ccc

Answer 2

:set textwidth=30

Answer 3

You can actually do two things:

1. Let vim format (i.e.change) your text to have shorter lines, by inserting linebreaks
2. Leave lines as they are, but display them wrapped

Which do you want?

1. would be achieved by setting textwidth (see Swaarop's answer). Then you can reformat your text by marking it (visual mode) and typing gq.

2. can be toggled by ":set wrap" / ":set nowrap"

Both are independent.

Answer 4

Once you set 'textwidth', you can select text with visual mode and press gq to wrap it nicely (you can also use Q on some older/legacy configurations).

A few useful tips:

gqgq (wrap the current line)
gq{ (wrap this 'paragraph', i.e. until the next blank line)
:h hq