$ find . -type f -name filename.exe -exec sed -i "s/oldstring/oldstring/g" {} +;
This is a slightly modified version of http://www.commandlinefu.com/commands/view/4283/recursive-search-and-replace-old-with-new-string-inside-files (which did not work due to incorrect syntax) with the added option to sed inside only files named filename.ext
by David Winterbottom (codeinthehole.com)
