The default Apache install in Ubuntu, and probably Debian too, contains a config file /etc/apache2/envvars which I have consistently ignored. I can’t remember ever having to deal with environment variables in a web application before.

But now I had to, and not realizing it, I spent a good hour fighting a vague problem from various angles, before I finally made the breakthrough.

This config file contains a line “LANG=C” by default. This has many consequences, but one of them is that all file operations in Ruby 1.9 expect files to be in ASCII encoding, while the rest of the system operates in UTF-8.

I ran into this with a Rails application hosted in Apache with Passenger, and a view containing non-ASCII characters. Ruby’s errors when it encounters incompatible encodings are… very terse.

But I imagine the reason that particular line in that particular config file is really there, because someone else banged his or her head against a wall for a good hour too, because LANG wasn’t C.