wiki/2020-09-16-23-09-01.org

:PROPERTIES:
:ID:       7827b564-59ed-4604-ac2b-630c60c0a4ab
:END:
#+title: Use timestamps for effectively future-proofing your stuff
#+date: "2020-09-16 23:09:01 +08:00"
#+date_modified: "2021-05-04 20:52:09 +08:00"
#+language: en


One of the simplest ways to future-proof your documents with [[id:ccb3bc14-a801-4ed0-b066-50b1bcd853aa][File metadata]] is to create a timestamp.
Specifically, two timestamps: one when it's created and one when it was last modified which will be continuously updated each time we modify the file.
This lets you quickly evaluate whether the information is up-to-date without relying on the filesystem.
It also lets you [[id:66337935-420c-40e6-81a6-f74ab0965ed5][Maintain your own digital library]] with relative ease if your focus is on up-to-date information.

In order to make updating the modification timestamp not tedious, it is best to automate that task.
Different files may be applied differently as long as we can create a unified interface to search through them all.

Here's an example with Org mode documents:

#+begin_src org  :exports none
\#+DATE: "2020-09-16 23:53:00 +08:00"
\#+DATE_MODIFIED: "2020-09-17 10:33:42 +08:00"
#+end_src

Emacs has a built-in time stamp feature that already took care of that task.
We can then attach the timestamp update with a hook that will occur before saving the file and voila!
Automated timestamp for our text documents. :D

Here's my (Doom Emacs) specific config as of 2020-09-17 for future references:

#+begin_src elisp
(after org!
  (setq
    ; Set a custom time-stamp pattern.
    ; Even though, it's not recommended, most of the time,
    time-stamp-start "DATE_MODIFIED:[ 	]+\\\\?[\"<]+"))

; Modify the time-stamp with each save.
(setq time-stamp-format "%Y-%02m-%02d %02H:%02M:%02S%:z")
(add-hook 'before-save-hook 'time-stamp)
#+end_src