Replacing on entiere set of files is hard in Emacs. But I find the correct mumbo-magic procedure, and gifted it to you:
- Call dired to list files in dir, or call find-dired if you need all sub directories.
- Mark the files you want. You can mark by regex by typing 【%m】.
- Type Q to call dired-do-query-replace-regexp.
- Type your find regex and replace string. (➲ common elisp regex pattern)
- For each occurrence, type y to replace, n to skip. Type 【Ctrl+g】 to abort the whole operation.
- Type ! to replace all occurrences in current file without asking, N to skip all possible replacement for rest of the current file. (N is emacs 23 only)
- To do the replacement on all files without further asking, type Y. (Emacs 23 only)
- Call ibuffer to list all opened files.
- Type 【*u】 to mark all unsaved files, type S to save all marked files, type D to close them all.