Commit each file in the current working directory using its time of last modification.

retrogit.sh

git ls-files -z --others --exclude-standard \
  | xargs -0 -I{} stat -c "%Y %n" "{}" \
  | sort \
  | cut -d' ' -f 2- \
  | while read -r name; do
      DATE=$(stat -c "%y" "$name")
      git add "$name"
      export GIT_AUTHOR_DATE="$DATE"
      export GIT_COMMITTER_DATE="$DATE"
      git commit -m "$name";
    done

git ls-files -z --modified --exclude-standard \
  | xargs -0 -I{} stat -c "%Y %n" "{}" \
  | sort \
  | cut -d' ' -f 2- \
  | while read -r name; do
      DATE=$(stat -c "%y" "$name")
      git add "$name"
      export GIT_AUTHOR_DATE="$DATE"
      export GIT_COMMITTER_DATE="$DATE"
      git commit -m "Updated $name";
    done