I have a custom Git hook in prepare-commit-msg that appends the date to the commit message so I don’t have to input it myself:

#!/bin/bash
#
# Append current `date` to commit messages

echo "`date +'%Y-%m-%d'`" >> $1

When I commit in my local repository, the date is appropriately appended to the Git commit message. However, when I push to GitHub, the commit message appears without the date appended. Why?

When committing, I ran the following command in Git Bash:

git commit -S -m "Refresh data" && git push

Is the intended message not appearing in GitHub because I combined git commit and git push in the same command perhaps? (I haven’t had a chance to try entering separate commands yet.)

(Aside: I realise git commits include a timestamp that contain the date. I want to insert the date for the sake of convenience. The point of this question is not to discuss the text being appended.)