This package provides an archiving functionality for org-mode, which makes sure archived entry is under the same heading hierarchy as it was in its original place.
(custom-set-variables
'(org-archive-default-command #'org-archive-mirror-subtree))
(with-eval-after-load 'org-agenda
(fset 'org-agenda-archive #'org-agenda-archive-default))
(define-key org-mode-map (kbd "C-c $") #'org-archive-subtree-default)By default an archive file is determined according to org-archive-location variable, but if you need to employ more complex logic then it allows, you can set org-archive-mirror-archive-file-function to a no-argument function, which, when invoked at the original heading location, must return a path to archive file.
Since version 29.1 Emacs got a "sibling file" concept, something like a test or a header file associated with source file (or vice versa), and a find-sibling-file command for switching to a sibling of current file. This facility enables quick switching between org file and its archive:
;;; adjust code as needed
;;; `org-directory' must be bound appropriately before evaluating this
(add-to-list
'find-sibling-rules
;; file.org → archive/file.org.gpg
(list
(rx-to-string (list 'and org-directory '(group "/" (+ not-newline) ".org") '(optional ".gpg") 'string-end) 'no-group)
(rx-to-string (list 'and org-directory "/archive" '(backref 1) ".gpg" 'string-end) 'no-group)))
(add-to-list
'find-sibling-rules
;; archive/file.org.gpg → file.org
(list
(rx-to-string (list 'and org-directory "/archive" '(group "/" (+ not-newline) ".org") ".gpg" 'string-end) 'no-group)
(rx-to-string (list 'and org-directory '(backref 1) '(optional ".gpg") 'string-end) 'no-group))))