Here’s a little trick to format XML in BBEdit and vi.

BBEdit can format markup, but none of its built-in styles do what I want. Like so often when working with XML, the awesome libxml library helps out. It comes with the xmllint command line utility, which formats XML in a way I like.

In BBEdit, I use it as a UNIX Filter by storing the following script as xmllint.sh in the $HOME/Library/Application Support/BBEdit/Text Filters/xml directory.

#!/bin/sh

XMLLINT_INDENT=$'\t' xmllint --format -

You can use spaces instead of a tab by changing \t.

It should show up in your UNIX Filters palette. Keep in mind that UNIX Filters in BBEdit operate on the selection or on the entire document if nothing is selected so you should make sure that there’s no selection.

The following version additionally performs some normalization (sort attribute order, unify attribute quotes etc.) by canonicalizing the output first.

#!/bin/sh

xmllint --c14n - | XMLLINT_INDENT=$'\t' xmllint --format -

The vi editor also has a filter feature. To format using xmllint, type this sequence:

:%!xmllint --format -

Or mark the area visually and then type

!xmllint --format -

The video shows these two:

Update May 2012: Adjusted the shell script snippets for BBEdit 10 and TextWrangler 4, which pass the text on STDIN instead of in a temp file. Also adjusted the location of text filter scripts inside BBEdit’s Application Support directory.