Why does ^#.*#$ not capture recursively inserted files?

Question

While considering some refactoring, I made changes throughout a project.

Halfway through the changes, and before saving, I found it doesn't quite work. I exited emacs and restarted. (That's probably not the right approach. There must be some kind of "ignore-all-changes-done-so-far" command I'm missing.)

Regardless, I now have many filename.ext that are left with a trail of #filename.ext#.

I recursively insert directories in dired-mode starting from the project root, and flag (%-d) all files of the regexp ^#.*#$ for deletion.

This expression only captures the files at the root of the hierarchy. Why, and how can I modify it to also catch all files inside the hierarchy?

Comparison

By way of comparison, marking (or flagging) all files of the pattern ^.*\.js$ does indeed catch all files, in both the root and in recursive directories. So why is ^#.*#$ not good?

Answer 1

I think you are asking how to flag all files whose names look like auto-save files—that is, files whose names begin and end with #.

In Dired (including vanilla Dired and Dired+), the key # does exactly that.

C-h k # says:

# runs the command dired-flag-auto-save-files, which is an interactive compiled Lisp function in dired.el.

It is bound to #, menu-bar mark mark-flag marks-flag-auto-save-files.

(dired-flag-auto-save-files &optional UNFLAG-P)

Flag for deletion files whose names suggest they are auto save files.

A prefix argument says to unmark or unflag those files instead.

See also the Emacs manual, node Flagging Many Files.

You can also find this command as menu-item Flag Auto-save Files in menu-bar menu Mark. (In Dired+ this menu item is in menu Marks, submenu Flag.)

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As for the question why regexp ^#.*#$ does not work (used with %d or %m, for example) in inserted subdirectories: It's because for subdirectories the full file name is picked up, i.e., including the directory part.

You can use regexp ^.*/?#.*#$ to do what you want for all #...# files in the current Dired buffer, i.e., including all inserted subdirs.