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Monday, December 8, 2008

Handy vim - easily generate properly formated bullet lists

This is a problem I run into fairly often, because I do a bit of hand-coding HTML from word files or other content that clients send me. When you cut and paste the items for a bullet list into an html document, they often come in one per line with no formatting (or sometimes they have a "*" at the start of each line.

Obviously you can create a macro to automate the process of putting <li> tags around each item, but there's an even faster way to do this using vi's powerful regular expression tools.

Of course, this will only be useful if you can use vi, a command-line text-editor. If you're on shared hosting or something, you may be out of luck. There is a windows version of vi, but I haven't really done more than mess with it a bit. If you're on OSX, you're probably in luck - you can use the console, and I think that it has vim installed, although it's been like eight years since I used OSX regularly.

First, figure out the lines that you want to change - you need to know the first and last line to apply the expression to. For example, let's stay they're lines 5-10 of the code.

Then apply the following regular expression by pressing ":" and then typing it in:
5,10 s/\(.*\)/\t<li>\1<\/li>/

The basic pattern here is s/pattern/replacement/. So, to break it apart sequentially:

5,10 - apply the pattern only to lines 5-10
s - subsitute
/\(.*\)/ - match this pattern - .* means all characters, the escaped parentheses around it tell vi to remember what was matched for use in the replacement
\t<li>\1<\/li> - the replacement portion of the pattern, the \1 is a stand-in for what was matched in the matching pattern, the rest of puts a tab and open LI tag in front, with a closing LI tag after.

Of course similar patterns can be used for all sorts of things, such as replacing variable names in code. Enjoy!

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