Script to count total lines changed by a specific author in git history in a given time frame.

count_lines_changed.sh

#!/bin/bash

# Script to count total lines changed by a specific author in git history
# Usage: ./count_lines_changed.sh -a "Author Name" -s "2024-01-01" -e "2025-04-10" -b "master"

# Default values
START_DATE="2024-01-01"
END_DATE="2025-04-10"
BRANCH="master"
AUTHOR=""

# Parse command line arguments
while getopts "a:s:e:b:h" opt; do
  case $opt in
    a) AUTHOR="$OPTARG" ;;
    s) START_DATE="$OPTARG" ;;
    e) END_DATE="$OPTARG" ;;
    b) BRANCH="$OPTARG" ;;
    h)
      echo "Usage: $0 -a \"Author Name\" [-s start_date] [-e end_date] [-b branch]"
      echo "  -a: Author name (required)"
      echo "  -s: Start date (default: 2024-01-01)"
      echo "  -e: End date (default: 2025-04-10)"
      echo "  -b: Branch name (default: master)"
      echo "  -h: Show this help message"
      exit 0
      ;;
    \?)
      echo "Invalid option: -$OPTARG" >&2
      exit 1
      ;;
  esac
done

# Check if author is provided
if [ -z "$AUTHOR" ]; then
  echo "Error: Author name is required"
  echo "Usage: $0 -a \"Author Name\" [-s start_date] [-e end_date] [-b branch]"
  exit 1
fi

echo "Counting lines changed by \"$AUTHOR\" on branch $BRANCH from $START_DATE to $END_DATE..."

# Get line changes statistics using the same precise command as git log
STATS=$(git log --author="$AUTHOR" --since="$START_DATE" --until="$END_DATE" $BRANCH --pretty=tformat: --numstat | awk '{ add += $1; subs += $2; loc += $1 - $2 } END { print add, subs, add + subs }')

ADDED=$(echo $STATS | cut -d' ' -f1)
REMOVED=$(echo $STATS | cut -d' ' -f2)
TOTAL=$(echo $STATS | cut -d' ' -f3)

# Handle empty result
if [ -z "$TOTAL" ]; then
  echo "No changes found for the specified author and time period."
  exit 0
fi

echo "Lines added:   $ADDED"
echo "Lines removed: $REMOVED"
echo "Total changes: $TOTAL"