FreeBSD pkgng Upgrade with shared library saving (Similar to `portmaster -w` and `portupgrade`)

pkg-upgrade.sh

#! /bin/sh

COMPAT_DIR=/usr/local/lib/compat/pkg

if ! [ -d ${COMPAT_DIR} ]; then
  mkdir -p ${COMPAT_DIR}
fi

pkg update

# Get a list of origins to be upgraded
installed_packages=$(pkg query '%o %v')
packages_to_upgrade=$({ echo "${installed_packages}"; pkg rquery '%o %v' ${installed_packages}; } | sort | uniq -u | awk '{print $1}' | uniq)

if [ -z "${packages_to_upgrade}" ]; then
  echo "Nothing to update"
  exit 0
fi

# Backup files of packages to be upgraded, that are in use
{ ldconfig -r | sed -e 's#.* ##' -e '1,2d' | grep -v ^${COMPAT_DIR}; pkg query '%Fp' ${packages_to_upgrade}; } | sort | uniq -d | while read file
do
  cp -pf ${file} ${COMPAT_DIR}/
done
/usr/sbin/service ldconfig start > /dev/null 2>&1

# Perform upgrade
pkg upgrade -U

# Cleanup duplicated libs
pkg query '%Fp' ${packages_to_upgrade} | while read file
do
  compat_file=${COMPAT_DIR}/${file##*/}
  if [ -f ${compat_file} ]; then
    echo "Removing duplicated shared library: ${compat_file}"
    rm -f ${compat_file}
  fi
done

/usr/sbin/service ldconfig start > /dev/null 2>&1