Compare hugo output across versions

hugo-compare.sh

#!/usr/bin/env bash

# Compares the output directory for two versions of Hugo (https://gohugo.io), so you
#   can know how updating to a new version will affect your content generation.


# exit on error
set -e

# the current Hugo project that I care about testing
REPO="$HUGO_REPO"

# only works for 64-bit Mac, but you can see how easy it would be to swap
MAC_SUFFIX="_macOS-64bit.tar.gz"
REL_PATTERN="https://github.com/gohugoio/hugo/releases/download/v%s/hugo_extended_%s%s"

if [[ $# -lt 2 ]]; then
  echo "Determining versions to check..."
  CURRENT_VERSION=$(hugo version | sed -n -E "s/^Hugo Static Site Generator v([^\/]*).*$/\1/p")
  BREW_VERSION=$(brew info hugo | grep "hugo: stable" | sed -n -E "s/hugo: stable ([^[:space:]]*).*$/\1/p")

  BUILD_A=$CURRENT_VERSION
  BUILD_B=$BREW_VERSION
else
  BUILD_A=$1
  BUILD_B=$2
fi

if [ $BUILD_A = $BUILD_B ]; then
  echo "Comparing $BUILD_A to itself? Nah."
  exit 1
fi

# download A
mkdir -p $(printf "hugo_%s" $BUILD_A)
URL_A=$(printf $REL_PATTERN $BUILD_A $BUILD_A $MAC_SUFFIX)
DL_TARGET_A=$(printf "hugo_%s/%s%s" $BUILD_A $BUILD_A $MAC_SUFFIX)

echo "Downloading $BUILD_A..."
wget -q $URL_A -O $DL_TARGET_A

# download B
mkdir -p $(printf "hugo_%s" $BUILD_B)
URL_B=$(printf $REL_PATTERN $BUILD_B $BUILD_B $MAC_SUFFIX)
DL_TARGET_B=$(printf "hugo_%s/%s%s" $BUILD_B $BUILD_B $MAC_SUFFIX)

echo "Downloading $BUILD_B..."
wget -q $URL_B -O $DL_TARGET_B

# clean pull of the repo
echo "Cloning repository..."
if [ -d "content_repo" ]; then
  rm -rf "content_repo"
fi
git clone $REPO content_repo --quiet

# expand the downloads
tar -xzf $DL_TARGET_A -C hugo_$BUILD_A
tar -xzf $DL_TARGET_B -C hugo_$BUILD_B

# build public site with each
echo "Building sites..."
hugo_$BUILD_A/hugo --quiet -s content_repo -d ../public_$BUILD_A
hugo_$BUILD_B/hugo --quiet -s content_repo -d ../public_$BUILD_B

echo "Running comparison..."
set +e
echo "------- DIFFERENCES"
git diff ./public_$BUILD_A ./public_$BUILD_B
echo "------- /DIFFERENCES"
set -e

echo "Cleaning up..."
rm -rf content_repo
rm -rf hugo_$BUILD_A
rm -rf hugo_$BUILD_B
rm -rf public_$BUILD_A
rm -rf public_$BUILD_B

echo "Done!"