Update all .png references to .jpg across a codebase using git status pairs

rename_png_refs.sh

#!/bin/bash
# After converting PNGs to JPEGs, update all references in the codebase.
# Parses git status for deleted .png / new .jpg pairs and does a global find-and-replace.
# Usage: ./rename_png_refs.sh [directory]

set -euo pipefail

DIR="${1:-.}"
DRY_RUN="${DRY_RUN:-false}"

# Get deleted .png bases (path without extension)
deleted_pngs=$(git status --porcelain | grep -E '^.D .*\.png$|^D  .*\.png$' | sed 's/^.\{3\}//' | sed 's/\.png$//' | sort)

# Get new .jpg bases
new_jpgs=$(git status --porcelain | grep -E '^\?\? .*\.jpg$|^A. .*\.jpg$' | sed 's/^.\{3\}//' | sed 's/\.jpg$//' | sort)

# Find common bases (the matched pairs)
pairs=$(comm -12 <(echo "$deleted_pngs") <(echo "$new_jpgs"))

if [ -z "$pairs" ]; then
  echo "No matching deleted .png / new .jpg pairs found in git status."
  exit 0
fi

num_pairs=$(echo "$pairs" | wc -l | tr -d ' ')
echo "Found ${num_pairs} png->jpg pairs to rename across codebase:"
echo ""

count=0
while IFS= read -r base; do
  [ -z "$base" ] && continue
  filename=$(basename "$base")
  old_ref="${filename}.png"
  new_ref="${filename}.jpg"

  hits=$(grep -rl --include='*.rb' --include='*.erb' --include='*.haml' --include='*.slim' \
    --include='*.html' --include='*.css' --include='*.scss' --include='*.sass' \
    --include='*.js' --include='*.ts' --include='*.tsx' --include='*.jsx' \
    --include='*.yml' --include='*.yaml' --include='*.json' --include='*.md' \
    "$old_ref" "$DIR" 2>/dev/null || true)

  if [ -z "$hits" ]; then
    echo "  $old_ref -> $new_ref (no references found)"
    count=$((count + 1))
    continue
  fi

  num_files=$(echo "$hits" | wc -l | tr -d ' ')

  if [ "$DRY_RUN" = "true" ]; then
    echo "  [dry-run] $old_ref -> $new_ref (${num_files} files)"
    echo "$hits" | sed 's/^/    /'
  else
    echo "$hits" | while IFS= read -r f; do
      sed -i '' "s|${old_ref}|${new_ref}|g" "$f"
    done
    echo "  $old_ref -> $new_ref (${num_files} files updated)"
  fi

  count=$((count + 1))
done <<< "$pairs"

echo ""
echo "Done: ${count} replacements processed."