reddit script critique

#!/bin/sh
# Enhanced backup script
# Sends messages to Zabbix based on exit code of borg executable
#
# email removed
# Shellcheck will still kvetch at you if notices are enabled
#
# This script will not work AS-IS but is only provided as such
# NO WARRANTIES
# This work is licensed under a Creative Commons Attribution 4.0 International License.
# https://creativecommons.org/licenses/by/4.0/
#
# 2017-08-10

####################
# SETUP
####################
ZABBIX_SERVER=monitor01.example.net
RUN_HOST="$(hostname)"
RUN_DATE="$(date +%Y-%m-%d-%R)"
SEND_CMD=/bin/zabbix_sender
BORG_CMD=/usr/local/bin/borg
REPOSITORY=borgbackup@backup01.example.net:/backup/${RUN_HOST}
export BORG_PASSPHRASE='REPLACEME'

####################
# BACKUP
####################
if [ -x ${BORG_CMD} ]
then
  echo "Starting backup on ${RUN_DATE}"
  ${BORG_CMD} create -v --stats            \
      "${REPOSITORY}"::"${RUN_HOST}"-"${RUN_DATE}" \
      /root                                \
      /home                                \
      /etc                                 \
      /opt                                 \
      /var/www/html
else
  echo "error with borg executable"
  ${SEND_CMD} -z ${ZABBIX_SERVER} -s "${RUN_HOST}" -k system.backup.state -o 3
  exit 1
fi

####################
# EXIT CODE CHECK
####################
case $? in
0)
  # Success
  echo "Backup completed successfully"
  ${SEND_CMD} -z ${ZABBIX_SERVER} -s "${RUN_HOST}" -k system.backup.state -o 0
  ;;
1)
  # Warning
  echo "Backup completed with warnings"
  ${SEND_CMD} -z ${ZABBIX_SERVER} -s "${RUN_HOST}" -k system.backup.state -o 1
  ;;
2)
  # Failure
  echo "Backup failed!"
  ${SEND_CMD} -z ${ZABBIX_SERVER} -s "${RUN_HOST}" -k system.backup.state -o 2
  exit 1
  ;;
*)
  # Unknown status
  echo "Backup status unknown"
  ${SEND_CMD} -z ${ZABBIX_SERVER} -s "${RUN_HOST}" -k system.backup.state -o 3
  ;;
esac

####################
# POST BACKUP PRUNE
####################
echo "Starting backup pruning"
${BORG_CMD} prune -v "$REPOSITORY" --prefix "${RUN_HOST}"- \
    --keep-daily=7 --keep-weekly=4 --keep-monthly=6