Get number of lines added and deleted per day from your git repo

git-line-add-delete-per-day.sh

#!/bin/bash

ds() {
  date --date="$1 days ago" +%Y-%m-%d
}

BRANCH=master # your branch here

echo "Date,LinesAdded,LinesDeleted"
for day in $(seq 1 10)
do
  lines=$(git --no-pager log --after=$(ds $day) --before=$(ds $(($day - 1))) --format=format: --numstat $BRANCH | awk '{s+=$1; t+=$2;} END {printf "+%s,-%s",$1,$2}')
  if [[ "$lines" != "+,-" ]]; then
      echo "$(ds $day),$lines"
  else
  	  echo "$(ds $day),0,0"
  fi
done

I forked it to take the script and number of days as an argument.
I also had trouble with the awk command on line 12 - I replaced $1,$2 with s,t at the end.