In no particular order, a quick run down of some things I learned this week (no particular order):

Ruby / Ruby on Rails

• In Ruby: don’t use f.readlines.each in a loop, as that waits for all output, then iterates.  Use f.readline instead, but be prepared to catch the EOF exception when you finish (it’s a documented part of that interface)
• In Ruby on Rails: rss is a valid format (at least in 2.2.2), and can be used in a builder

Mono / C#

• In Mono: File.Exists fails on directories.  Even though directories are just special files in Linux, the implementation decided that wasn’t right.  Use Directory.Exists instead.

Networking

• IPv6 finally made sense to me, after implementing a 3 site topology for my Network Lab graduate class.