pre-commit git hook for crushing images

pre-commit.sh

#!/bin/sh
# to use, save this file as .git/hooks/pre-commit in your git repo
# make sure to add execute permissions using: chmod +x .git/hooks/pre-commit
command -v imgo >/dev/null 2>&1 || {
    echo "\033[1mPlease install imgo to reduce images size before commit\033[0m"
    echo "Install imgo with the following:"
    echo "\t \033[1mnpm install -g imgo\033[0m"
    exit 1;
}

for file in `git diff --cached --name-status|awk '$1 ~ /[AM]/ && tolower($2) ~ /\.png$/ {print $2}'`
do
echo "Optimizing $file"
  cat $file | imgo --pngquant --zopflipng > ${file%.png}.new
  mv -f ${file%.png}.new $file
  git add $file
done

for file in `git diff --cached --name-status|awk '$1 ~ /[AM]/ && tolower($2) ~ /\.jpe?g$/ {print $2}'`
do
echo "Optimizing $file"
  cat $file | imgo --jpegoptim --jpegRecompress --mozjpeg > ${file%.jpg}.new
  mv -f ${file%.jpg}.new $file
  git add $file
done

for file in `git diff --cached --name-status|awk '$1 ~ /[AM]/ && tolower($2) ~ /\.gif$/ {print $2}'`
do
echo "Optimizing $file"
  cat $file | imgo --gifsicle > ${file%.gif}.new
  mv -f ${file%.gif}.new $file
  git add $file
done

for file in `git diff --cached --name-status|awk '$1 ~ /[AM]/ && tolower($2) ~ /\.svg$/ {print $2}'`
do
echo "Optimizing $file"
  cat $file | imgo --svgo > ${file%.svg}.new
  mv -f ${file%.svg}.new $file
  git add $file
done