gitsize - size diffs in two commits

1.sh

# Displays size diff between two commits
# http://stackoverflow.com/a/10847242/472153
function gitsize()
{
  args=$(git rev-parse --sq "$@")
  eval "git diff-tree -r $args" | {
    total=0
    while read A B C D M P
    do
      case $M in
        M) bytes=$(( $(git cat-file -s $D) - $(git cat-file -s $C) )) ;;
        A) bytes=$(git cat-file -s $D) ;;
        D) bytes=-$(git cat-file -s $C) ;;
        *)
          echo >&2 warning: unhandled mode $M in \"$A $B $C $D $M $P\"
          continue
          ;;
      esac
      total=$(( $total + $bytes ))
      printf '%d\t%s\n' $bytes "$P"
    done
    echo total $total
  }
}

2.sh

# After optimizing some images ..

$ gitsize 308614f 7a29d97
-2073	content/statics/ansible.png
-2694	content/statics/aws.png
-664	content/statics/blog/barrels.jpg
-69620	content/statics/blog/orderedlistocat.png
...
total -263551
$