Quick shell script to list the actual size on disk of what git has stored for each commit in a repo.

list_git_commit_sizes.zsh

#!/bin/zsh

git rev-list --all|
	while read sha; do
		let total=0
		git diff-tree -r -c -M -C --no-commit-id $sha |
			cut -d' ' -f3 |
			while read blob; do
				case $blob in
					0000000000000000000000000000000000000000)
						continue
						;;
					*)
						let total+=$(git cat-file -s $blob)
						;;
				esac
			done
		echo "${sha[0,7]} $total"
	done