ack -a to search all files.

ack is an excellent replacement for grep. Usually it only searches known filetypes, and that is sufficient for most cases. But if you want to search the content source tree of your static Web site, which uses a funky file extension, ack alone will skip it.

`$ ack -a the-search-string`

This will still skip things like version control files, but it will check those content source fiels with the funky file extension.

From: perldoc ack - HTMLified