How can I recursively find and replace text in case sensetive?

Question

I am using combination of following solutions in order to find-and-replace matched text in all Python files:

• Using Emacs to recursively find and replace in text files not already open

• How can I recursively find and replace in the current git repository

I observe that when I want to replace capital words like "HELLO_WORLD" , it also replaces hello_world string as well.

(setq case-fold-search nil)

(defun find-and-replace ()
  (interactive)
  (message "press t to toggle mark for all files found && Press Q for Query-Replace in Files...")
  (find-dired (vc-git-root (buffer-file-name)) "-name \\*.py -o ! -name flycheck_\\*.py ! -name __init__.py ! -name \".*\" ! -name build ! -path \\*/.eggs/\\*"))

M-x find-and-replace ; then t to toggle marked/unmarked files (thus marking them all, since none were marked). Then I use Q to use query-replace on the marked files. And enter HELLO_WORLD to replace with WORLD_HELLO.

How can I fix find-and-replace to work in case-sensetive?

Answer 1

As already mentioned in the comments the variable case-fold-search is buffer-local.

The following line in your init file sets this variable only for the buffer to nil where the init file is evaluated:

(setq case-fold-search nil)

To change the default value that is valid in all buffers where case-fold-search is not explicitly set you need to set the default value of case-fold-search:

(setq-default case-fold-search nil)