On Ubuntu:
git commit --amend --date `date -Iseconds --date "\date -Iseconds` -12 hours"`
On macOS:
GIT_AUTHOR_DATE=`date -R -v-5H`
GIT_COMMITER_DATE=$GIT_AUTHOR_DATE
git commit --amend --date "$GIT_AUTHOR_DATE"
Personal Homepage
On Ubuntu:
git commit --amend --date `date -Iseconds --date "\date -Iseconds` -12 hours"`
On macOS:
GIT_AUTHOR_DATE=`date -R -v-5H`
GIT_COMMITER_DATE=$GIT_AUTHOR_DATE
git commit --amend --date "$GIT_AUTHOR_DATE"