You don't want to be creating an array like this within the template. The point of eco templates it to separate the logic/data from the presentation. Declare the data separately, then use it to render the template.
Like this
eco = require "eco"
fs = require "fs"
template = fs.readFileSync __dirname + "/views/test.html.eco", "utf-8"
console.log eco.render template, links: [
{url:"https://github.com/drguildo", icon:"github"},
{url:"http://www.flickr.com/photos/drguildo/", icon:"flickr"},
{url:"http://instagram.com/therac25", icon:"instagram"},
{url:"http://www.last.fm/user/drguildo", icon:"lastfm"}
]
and then just
<% for link in @links: %>
<a href="<%= link.url %>"><img src="/img/icons/<%= link.icon %>.png" /></a>
<% end %>