Neatening Lines (Unix Power Tools, 3rd Edition)

17.28. Neatening Lines

Have you made edits that left some of your lines too short or long? The fmt (Section 21.2) utility can clean that up. Here's an example. Let's say you're editing a file (email message, whatever) in vi and the lines aren't even. They look like this:

This file is a mess
with some short lines
and some lines that are too long -- like this one, which goes on and on for quite 
a while and etc.

Let's see what 'fmt' does with it.

You put your cursor on the first line and type (in command mode):

5!! Section 17.18

5!!fmt

which means "filter (Section 17.18) 5 lines through fmt." Then the lines will look like this:

This file is a mess with some short lines and some lines that are too
long -- like this one, which goes on and on for quite a while and etc.

Let's see what 'fmt' does with it.

This is handiest for formatting paragraphs. Put your cursor on the first line of the paragraph and type (in command mode):

!}fmt

If you don't have any text in your file that needs to be kept as is, you can neaten the whole file at once by typing:

% Section 20.3

:%!fmt

There are a few different versions of fmt, some fancier than others. Most of the articles in Chapter 21 about editing-related tools can be handy too. For example, recomment reformats program comment blocks. cut (Section 21.14) can remove columns, fields, or shorten lines; tr (Section 21.11) can do other transformations. To neaten columns, try filtering through with the setup in Section 21.17. In general, if the utility will read its standard input and write converted text to its standard output, you can use the utility as a vi filter.

-- JP